JPH03107731A - Infrared sensor - Google Patents
Infrared sensorInfo
- Publication number
- JPH03107731A JPH03107731A JP24568989A JP24568989A JPH03107731A JP H03107731 A JPH03107731 A JP H03107731A JP 24568989 A JP24568989 A JP 24568989A JP 24568989 A JP24568989 A JP 24568989A JP H03107731 A JPH03107731 A JP H03107731A
- Authority
- JP
- Japan
- Prior art keywords
- liquid crystal
- cap
- infrared rays
- infrared
- crystal element
- 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.)
- Pending
Links
- 239000004973 liquid crystal related substance Substances 0.000 claims abstract description 42
- 230000005611 electricity Effects 0.000 abstract 1
- 230000001678 irradiating effect Effects 0.000 abstract 1
- 238000010586 diagram Methods 0.000 description 9
- 238000005259 measurement Methods 0.000 description 5
- 239000000758 substrate Substances 0.000 description 4
- 238000000149 argon plasma sintering Methods 0.000 description 3
- 239000000463 material Substances 0.000 description 2
- 101150034533 ATIC gene Proteins 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- WABPQHHGFIMREM-UHFFFAOYSA-N lead(0) Chemical compound [Pb] WABPQHHGFIMREM-UHFFFAOYSA-N 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
Landscapes
- Photometry And Measurement Of Optical Pulse Characteristics (AREA)
- Radiation Pyrometers (AREA)
Abstract
Description
【発明の詳細な説明】 （イ）産業上の利用分野 本発明は赤外線センサに関する。[Detailed description of the invention] (b) Industrial application field The present invention relates to an infrared sensor.
（ロ）従来の技術
従来、焦電体を用いた赤外線センサには、チョッパと呼
ばれる赤外線の光量を周期的に変化させる装置が必要で
ある。このセンサのチョッパには、回転体又は振動体等
が用いられているが、構造が大型になり、コスト的にも
高く、消費電力やノイズが大きいといった欠点があった
。そこで、静止型で小型化が可能なものとして液晶の電
気光学効果を用いた赤外線調光素子が提案されている（
特開昭５９−１５８０８９号公報、特開昭６１−２５４
８２５号公報、特開昭６２−２３４１２４号公報参照）
。既に公開されている公報の中で、特開昭６２−２３４
１２４号公報には、 Ｔ Ｎ （Ｔｗｉｓｔｅｄ Ｎｅ
ｏ＋ａｔｉｃ）型といわれる液晶を利用することが記載
されているが、現在、ＴＮｐ！：！の他には、光散乱を
利用して光量を調整するＤＳＭ型もある。(B) Prior Art Conventionally, infrared sensors using pyroelectric materials require a device called a chopper that periodically changes the amount of infrared light. The chopper of this sensor uses a rotating body, a vibrating body, or the like, but has disadvantages such as a large structure, high cost, high power consumption, and high noise. Therefore, an infrared light control element that uses the electro-optic effect of liquid crystal has been proposed as a stationary type device that can be miniaturized (
JP-A-59-158089, JP-A-61-254
825, JP-A-62-234124)
. Among the gazettes already published, JP-A-62-234
In Publication No. 124, T N (Twisted Ne
It has been described that a liquid crystal called "o+atic" type is used, but currently, TNp! :! There is also a DSM type that uses light scattering to adjust the amount of light.
そこで、液晶素子を用いた赤外線センサの一例を第２図
に示す。支持台（３０）上に焦電素ｆ−（３１）が取り
付けられ、この焦電素７’ （３１’）を覆うキャップ
（３２）が設けられており、このキャップ（３２）には
赤外線を焦電素子（３１）にまで導く窓部（３３）が開
かれている。そして、このキャップ（３２）の窓部（３
３）上に液晶素子（３４）が配置されていて、この液晶
素子（３４）への給電を周期的に行うことによって、焦
電素子（３１）へのチョッピングを行う構成を採ってい
る。FIG. 2 shows an example of an infrared sensor using a liquid crystal element. A pyroelectric element f-(31) is mounted on a support base (30), and a cap (32) is provided to cover this pyroelectric element 7'(31'). A window (33) leading to the pyroelectric element (31) is opened. The window (3) of this cap (32)
3) A liquid crystal element (34) is disposed above, and a configuration is adopted in which chopping to the pyroelectric element (31) is performed by periodically supplying power to the liquid crystal element (34).
（ハ）発明が解決しようとする課題
しかし、に述した構造のセンサを用いる場０合、センサ
の感度及び精度に不充分な点があった。(c) Problems to be Solved by the Invention However, when using a sensor having the structure described in (3) above, the sensitivity and accuracy of the sensor are insufficient.
（ニ）課題を解決するための手段
本発明による赤外線センサは、支持台上に取り付けられ
た焦電素子と、この素子の前面に配置され、該素子に対
してチョッパの働きを成すための液晶素子と、前記焦電
素子及び液晶素子を筺うキャップと、を備え、このキャ
ップには上記液晶素子を介して焦′ｔｋ素トへ赤外線を
導入する窓部が設けられていることから成っている。(d) Means for Solving the Problems The infrared sensor according to the present invention includes a pyroelectric element mounted on a support base, and a liquid crystal display disposed in front of the element to act as a chopper for the element. and a cap housing the pyroelectric element and the liquid crystal element, and the cap is provided with a window portion for introducing infrared rays into the pyroelectric element through the liquid crystal element. There is.
（ホ）作用
本発明によれば、キャップに設けられた窓部から赤外線
が照射され、液晶素子表面に到達し、赤外線の光量を周
期的に変化させ、焦電Ｘｆ−により赤外線を感知してい
る。(E) Function According to the present invention, infrared rays are irradiated from the window provided in the cap, reach the surface of the liquid crystal element, change the amount of infrared rays periodically, and sense the infrared rays by pyroelectric Xf-. There is.
（へ）実施例
以下、本発明の一実施例を図面を用いて詳細に説明する
。第１図は本発明による赤外線センサの側面断面図を例
示したものである。（１）は焦電素子で、ステムなどの
支持台（２）ｔに設けられている。支持台（２）には焦
電素子（１）を被せるように液晶素子支持具（３）を設
置し、この支持具（３）上に液晶素ｆ（４）が取り付け
られている。この液晶素子（４）は２枚の透明基板（５
）（５）と、その基板（５）（５）に挟まれた微少空隔
（セルギャップ１５μｍ）に封入された液晶材料、例え
ばＮ１）−５（Ｃ１，０−−Ｎ＝Ｎ−−Ｃ，Ｈ，、、バ
ラアゾキシアニソール、ｌルク・ノヤパ・製）とから成
っている。この液晶素ト（４）を駆動する動作形態とし
てＤＳＭｙ！：ｌを用いている。（６）は液晶素子−＜
４＞に対するリード線であり、基板（５）から支持台（
２）へと連なっている。(F) Example Hereinafter, an example of the present invention will be described in detail with reference to the drawings. FIG. 1 illustrates a side sectional view of an infrared sensor according to the present invention. (1) is a pyroelectric element, which is provided on a support base (2) t such as a stem. A liquid crystal element support (3) is installed on the support base (2) so as to cover the pyroelectric element (1), and a liquid crystal element f (4) is mounted on this support (3). This liquid crystal element (4) consists of two transparent substrates (5
) (5) and the liquid crystal material sealed in the microscopic gap (cell gap 15 μm) sandwiched between the substrates (5) (5), such as N1)-5(C1,0--N=N--C , H, , roseazoxyanisole (manufactured by Luc Noyapa). DSMy! is the operating mode for driving this liquid crystal element (4). :l is used. (6) is a liquid crystal element -<
4>, and is a lead wire from the substrate (5) to the support base (
It is connected to 2).
（７）は焦電ＸＦ（１）及び液晶素子−（４）を覆うキ
ャップで、支持台（２）上に設置されており、このキャ
ップ（７）には液晶２ｆ（４）を介して焦電素ｒ−（＋
）へ赤外線を導くと共に、液晶素−７−（４）での光散
乱を防止する窓部（８）が設けられている。この装置の
大きさは、支持台（２）より基板（５）までが高さ１５
■、液晶素子（４）の厚さ１ｍ、そしてキャップ（７）
の厚さがｌＯ閣である。(7) is a cap that covers the pyroelectric XF (1) and the liquid crystal element (4), which is installed on the support base (2), and is attached to the cap (7) through the liquid crystal 2f (4). Electron r-(+
) is provided with a window portion (8) that guides infrared rays to the liquid crystal element-7-(4) and prevents light scattering at the liquid crystal element-7-(4). The size of this device is 15 cm in height from the support base (2) to the substrate (5).
■, thickness of liquid crystal element (4) 1m, and cap (7)
The thickness of is 10mm.
このように構成された赤外線センサにおいて、赤外線は
キャップ（７）の窓部（８）を通して到来する。In the infrared sensor configured in this way, infrared rays arrive through the window (8) of the cap (7).
−・方、液晶素子（４）への給電を１８期的に行うこと
によって、この液晶素子（４）は該素子（４）を透過す
る赤外線を周期的に変化させる。従って、キャップ（７
）の窓部（８）を通して到来する赤外線の光量が周期的
に変化するので焦電素子（１）が赤外線を検知してセン
サ機能を発揮する。- On the other hand, by periodically supplying power to the liquid crystal element (4), the liquid crystal element (4) periodically changes the infrared rays transmitted through the element (4). Therefore, the cap (7
) The amount of infrared light arriving through the window (8) changes periodically, so the pyroelectric element (1) detects the infrared light and performs a sensor function.
次に、赤外線センサの出力評価における各種の条件につ
いて第３図を用いて説明する。Next, various conditions for evaluating the output of the infrared sensor will be explained using FIG. 3.
ここで、（１）は焦を素子で、（４）は液晶素ｆである
。（１１）はロックインアンプで、（１２）は液晶素子
駆動回路、（１３）は赤外線放射体である。この赤外線
放射体（１３）の表面温度を１００℃とし、液晶素子駆
動回路（１２）により液晶素′Ｉ−（４）を作動させ、
ロックインアンプ（１１）で、焦電素Ｆ（＋）に生ずる
出力を測定した。また、第４図は液晶素子（４）に印加
する電圧を示した駆動波形図で、±２５ＶレベルでＯＮ
、０レベルでＯＦＦとなるので、ｌ Ｈｚの周期でＯＮ
、ＯＦＦ変化させていることになる。Here, (1) is a crystal element, and (4) is a liquid crystal element f. (11) is a lock-in amplifier, (12) is a liquid crystal element drive circuit, and (13) is an infrared radiator. The surface temperature of this infrared radiator (13) is set to 100°C, and the liquid crystal element 'I-(4) is operated by the liquid crystal element drive circuit (12).
The lock-in amplifier (11) measured the output generated in the pyroelectric element F(+). In addition, Figure 4 is a drive waveform diagram showing the voltage applied to the liquid crystal element (4), which turns on at a ±25V level.
, it turns off at 0 level, so it turns on with a cycle of l Hz.
, this means that the OFF state is changed.
この測定条件丁における測定結果を第５図に示す。第５
図は視野角（１８−２６’ ）と出力との関係を示して
おり、く実＠Ａ＞は本発明の赤外線センサ、く破線Ｈ＞
は第２図に示した従来構造の特性図である。この図より
明らかな様に、従来構造と比較すると、同じ視野角の場
合、本発明の赤外線センサ〈実ｇｌｌＡ＞の方が出力が
大きいことが判る。The measurement results under these measurement conditions are shown in FIG. Fifth
The figure shows the relationship between the viewing angle (18-26') and the output.
is a characteristic diagram of the conventional structure shown in FIG. As is clear from this figure, when compared with the conventional structure, it can be seen that the infrared sensor of the present invention (actual gllA) has a larger output at the same viewing angle.
次に、第６図は視野角を２２，４°に固定し、両センサ
と赤外線放射体（１３）との距ｉ！ｔ（ｄ ）を変化さ
せて出力測定し比較した特性図である。図より本発明の
赤外線センサ〈実線ａ〉の方が従来の赤外線センサく破
線ｂ〉よりも出力は一定で、従来の赤！Ｉ＋線センサ〈
破線１）＞では距離依存性が見られ、センサとしての性
能が劣ることが判る。Next, in FIG. 6, the viewing angle is fixed at 22.4°, and the distance i! between both sensors and the infrared emitter (13) is ! It is a characteristic diagram in which the output was measured and compared while changing t(d). The figure shows that the output of the infrared sensor of the present invention (solid line a) is more constant than that of the conventional infrared sensor (broken line b), and the output of the infrared sensor of the present invention (solid line a) is more constant than the conventional infrared sensor (broken line b). I+ line sensor
In the dashed line 1)>, distance dependence is seen, indicating that the performance as a sensor is poor.
さらに、第７図は本発明の赤外線センサにおいて、赤外
線がキャップ（７）の窓部（８）より入り、液晶ｇｆｃ
４＞に達する迄のキャップ（７）の厚みを変えて、その
出力測定の結果を示した特性図である。図より朗らかに
キャップ（７）の厚みが太き（なる程、出力は大きくな
ることが判る。Furthermore, in the infrared sensor of the present invention, FIG. 7 shows that infrared rays enter through the window (8) of the cap (7) and
4> is a characteristic diagram showing the results of output measurement while changing the thickness of the cap (7). As you can clearly see from the figure, the thickness of the cap (7) is thicker (the more the output is increased).
続いて、第８図はセンサの出力を比較するために設けた
３種類のセンサの側面断面図を例示したものである。従
来の赤外線センサ（ア）、本発明の赤外線センサでキャ
ップ（７）の厚みを薄く形成させた場合（イ）、本発明
の赤外線センサでキャップ（７）の厚みを火き（形成さ
せた場合（つ）を比較し、視野角及びセンサと赤外線放
射体（１３）の距離を一定として、出力測定すると、
（ア）＜（イ）〈（つ）
という出力測定結果となる。これはＤＳＭ型液晶Ｘｆに
おいて、電圧の印加状態をＯＮ状１ｓ（チヨ・ｌパ閉状
！！りにすると、視野外からの赤外線が液晶チョッパに
より光ｉ′１５Ｃ乱されてセンサに到達すると考えられ
、赤外線をより正確に検知するためには、より厚く作ら
れたキャップを用い、液晶素子に対する光散乱を防ぐよ
うにすると、センサの出力は高く、精度は向上する。Next, FIG. 8 illustrates side sectional views of three types of sensors provided for comparing the outputs of the sensors. A conventional infrared sensor (A), a case in which the infrared sensor of the present invention is used to reduce the thickness of the cap (7) (B), a case in which the infrared sensor of the present invention is used to reduce the thickness of the cap (7) If you compare (1) and measure the output while keeping the viewing angle and the distance between the sensor and the infrared emitter (13) constant, you will get the following output measurement results: (A) < (B) < (T). In the liquid crystal Xf, when the voltage application state is set to the ON state 1s (Closed state!!), it is thought that infrared rays from outside the field of view are disturbed by the liquid crystal chopper and reach the sensor, making the infrared rays more For accurate detection, a thicker cap is used to prevent light scattering against the liquid crystal element, which increases sensor output and improves accuracy.
（ト）発明の効果
本発明によれば、支持台上に取り付けられた焦電素子と
、この素ｆの前面に配置され、該素子に対してチョッパ
の動きを成すための液晶素ｆと、前記焦電素子及び液晶
素子を覆うキャップと、を備え、このキャップには上記
液晶素子を介して焦電素ナヘ赤外線を導入する窓部が設
けられているので、従来のセンサに比ベセンサの出力が
大きく、精度のよいものを得ることができる。(G) Effects of the Invention According to the present invention, a pyroelectric element is mounted on a support base, a liquid crystal element f is arranged in front of the element f, and is configured to perform a chopper movement with respect to the element; and a cap that covers the pyroelectric element and the liquid crystal element, and the cap is provided with a window portion that introduces infrared rays into the pyroelectric element through the liquid crystal element, so that the output of the sensor is lower than that of conventional sensors. It is possible to obtain large and accurate results.
又、そのセンサのキャップは赤外線を感知可能な限り厚
く形成すると、より−・層性能の良いセンサを得ること
ができる。Furthermore, if the cap of the sensor is made as thick as possible to detect infrared rays, a sensor with better layer performance can be obtained.
第１図は本発明の赤外線センサの側面断面図、第２図は
従来の赤外線センサを示した側面断面図、第３図は赤外
線センサの測定系を示すための構成図、第４図は液晶素
子に印加する゛電圧を示す駆動波形図、第５図は赤外線
センサの視野角を変化させた場合の特性図、第６図は赤
外線センサのセンサと赤外線放射体との距離を変化させ
た場合の特性図、第７図は赤外線センサのキャップの厚
みと視野角を変化させた場合の特性図、第８図は３種類
の赤外線センサを比較した側面断面図である。
（ｌ ０３１）・・・焦電素子−１
（２）（３０）・・・支持台、
（４）（３４）・・・液晶素子、
（７）（３２）・・・キャップ、
（８）（３３）・・・窓部。Figure 1 is a side sectional view of an infrared sensor of the present invention, Figure 2 is a side sectional view of a conventional infrared sensor, Figure 3 is a configuration diagram showing the measurement system of the infrared sensor, and Figure 4 is a liquid crystal display. A driving waveform diagram showing the voltage applied to the element. Figure 5 is a characteristic diagram when the viewing angle of the infrared sensor is changed. Figure 6 is a diagram when the distance between the infrared sensor and the infrared emitter is changed. FIG. 7 is a characteristic diagram when the cap thickness and viewing angle of the infrared sensor are varied, and FIG. 8 is a side sectional view comparing three types of infrared sensors. (l 031)...Pyroelectric element-1 (2)(30)...Support stand, (4)(34)...Liquid crystal element, (7)(32)...Cap, (8) (33)...window section.
Claims (2)
の前面に配置され、該素子に対してチョッパの働きを成
すための液晶素子と、前記焦電素子及び液晶素子を覆う
キャップと、を備え、このキャップには上記液晶素子を
介して焦電素子へ赤外線を導入する窓部が設けられてい
ることを特徴とする赤外線センサ。(1) A pyroelectric element mounted on a support base, a liquid crystal element placed in front of the element and serving as a chopper for the element, and a cap covering the pyroelectric element and liquid crystal element. An infrared sensor, characterized in that the cap is provided with a window portion that introduces infrared rays to the pyroelectric element through the liquid crystal element.
おいて、液晶素子に赤外線が到達する迄の前記キャップ
の厚さを前記焦電素子が赤外線を感知可能程度に大きく
形成させることを特徴とする請求項（１）記載の赤外線
センサ。(2) In the cap that covers the pyroelectric element and the liquid crystal element, the thickness of the cap is made large enough to allow the pyroelectric element to detect infrared rays until the infrared rays reach the liquid crystal element. The infrared sensor according to claim (1).
Priority Applications (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP24568989A JPH03107731A (en) | 1989-09-21 | 1989-09-21 | Infrared sensor |
| EP90103261A EP0384409B1 (en) | 1989-02-20 | 1990-02-20 | Infrared sensor comprising a liquid crystal chopper |
| US07/481,277 US5036199A (en) | 1989-02-20 | 1990-02-20 | Liquid crystal chopper and infrared sensor |
| DE69013375T DE69013375T2 (en) | 1989-02-20 | 1990-02-20 | Infrared sensor with a liquid crystal switch. |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP24568989A JPH03107731A (en) | 1989-09-21 | 1989-09-21 | Infrared sensor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH03107731A true JPH03107731A (en) | 1991-05-08 |
Family
ID=17137349
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP24568989A Pending JPH03107731A (en) | 1989-02-20 | 1989-09-21 | Infrared sensor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH03107731A (en) |
-
1989
- 1989-09-21 JP JP24568989A patent/JPH03107731A/en active Pending
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