JPH05187918A - Pyroelectric element - Google Patents
Pyroelectric elementInfo
- Publication number
- JPH05187918A JPH05187918A JP4021918A JP2191892A JPH05187918A JP H05187918 A JPH05187918 A JP H05187918A JP 4021918 A JP4021918 A JP 4021918A JP 2191892 A JP2191892 A JP 2191892A JP H05187918 A JPH05187918 A JP H05187918A
- Authority
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- Japan
- Prior art keywords
- electrodes
- pyroelectric
- electrode
- light receiving
- substrate
- 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.)
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- Radiation Pyrometers (AREA)
- Photometry And Measurement Of Optical Pulse Characteristics (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】この発明は、焦電素子に関し、詳
しくは、焦電型赤外線センサなどに用いられる焦電素子
に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pyroelectric element, and more particularly to a pyroelectric element used in a pyroelectric infrared sensor or the like.
【０００２】[0002]
【従来の技術】焦電型赤外線センサは、例えば、図３に
示すように、上面に電極２６が形成された基板２２を、
端子２７を有する金属製のステム２８上に載置し、基板
２２上に、焦電素子２３、抵抗チップ（リーク用抵抗）
２４、ＦＥＴ２５などを配設するとともに、リフロー半
田などの方法により、ステムピン２７ａ，抵抗チップ２
４，ＦＥＴ２５などを電極２６に半田付けし、これらの
各素子を、目的の波長を通過させるシリコン系材料など
からなる光学フィルタ（窓）２９を取り付けた金属製の
キャン３０を用いて封止することにより形成されてい
る。2. Description of the Related Art A pyroelectric infrared sensor, for example, as shown in FIG. 3, includes a substrate 22 having an electrode 26 formed on its upper surface.
It is placed on a metal stem 28 having a terminal 27, and a pyroelectric element 23 and a resistor chip (leakage resistor) on the substrate 22.
24, the FET 25, etc., and the stem pin 27a, the resistance chip 2 and the like by a method such as reflow soldering.
4, the FET 25 or the like is soldered to the electrode 26, and each of these elements is sealed using a metal can 30 having an optical filter (window) 29 made of a silicon-based material or the like that allows passage of a target wavelength. It is formed by
【０００３】このような焦電型赤外線センサにおいて用
いられる焦電素子２３は、図４に示すように、焦電体
（焦電基板）４０の一方の主面（受光面）に２つの受光
電極３１ａ，３１ｂを配設し、これを接続電極３５で接
続するとともに、図５に示すように、他方の主面（裏
面）に、上記受光電極３１ａ及び３１ｂと対向するとと
もに、焦電基板４０の端部にまで達する２つの裏面電極
（対向電極）３２ａ，３２ｂを配設することにより形成
されている。As shown in FIG. 4, a pyroelectric element 23 used in such a pyroelectric infrared sensor has two light receiving electrodes on one main surface (light receiving surface) of a pyroelectric body (pyroelectric substrate) 40. 31a and 31b are arranged and connected to each other by the connection electrode 35. As shown in FIG. 5, the other main surface (back surface) faces the light receiving electrodes 31a and 31b, and the pyroelectric substrate 40 has It is formed by arranging two back surface electrodes (counter electrodes) 32a and 32b reaching the ends.
【０００４】[0004]
【発明が解決しようとする課題】しかし、上記従来の焦
電素子においては、焦電基板４０の他方の主面（裏面）
に形成された裏面電極（対向電極）３２ａ，３２ｂが、
受光電極３１ａ，３１ｂと対向する対向電極部、取付電
極部（ＦＥＴなどの外部の素子との電気的接続のために
半田付けや導電ペーストの塗布などが行われる電極部）
及び対向電極部と取付電極部を接続するリード電極部を
兼ねており、その寸法が大きく、広い面積に形成されて
いる。そのため、大きなストレー容量が形成され、焦電
素子全体の静電容量（素子容量）が増大するとともに、
裏面電極（対向電極）全体の面積が大きいため、熱容量
が大きくなり電圧感度が低下するという問題点がある。However, in the above-mentioned conventional pyroelectric element, the other main surface (back surface) of the pyroelectric substrate 40 is used.
Back electrodes (counter electrodes) 32a, 32b formed on
A counter electrode portion facing the light receiving electrodes 31a and 31b, a mounting electrode portion (an electrode portion where soldering or application of a conductive paste is performed for electrical connection with an external element such as an FET)
It also serves as a lead electrode portion that connects the counter electrode portion and the mounting electrode portion, and has a large size and is formed in a wide area. Therefore, a large stray capacitance is formed, and the electrostatic capacitance (element capacitance) of the entire pyroelectric element increases,
Since the total area of the back electrode (counter electrode) is large, there is a problem that the heat capacity becomes large and the voltage sensitivity is lowered.
【０００５】この発明は、上記問題点を解決するもので
あり、熱容量及び静電容量が小さく、電圧感度に優れた
焦電型赤外線センサなどに用いられる焦電素子を提供す
ることを目的とする。The present invention is intended to solve the above problems, and an object of the present invention is to provide a pyroelectric element used for a pyroelectric infrared sensor having a small heat capacity and a small electrostatic capacity and an excellent voltage sensitivity. ..
【０００６】[0006]
【課題を解決するための手段】上記目的を達成するため
に、この発明の焦電素子は、焦電基板の一方の主面であ
る受光面に、接続電極により接続された２つの受光電極
を配設し、焦電基板の他方の主面に、前記受光電極と略
同一の形状を有し、前記受光電極と対向する２つの対向
電極を配設するとともに、焦電基板の他方の主面の両端
部に外部接続用の取付電極を配設し、前記対向電極と前
記取付電極とを前記対向電極より幅の狭いリード電極に
より接続したことを特徴とする。In order to achieve the above object, a pyroelectric element of the present invention has two light receiving electrodes connected by a connecting electrode on a light receiving surface which is one main surface of a pyroelectric substrate. On the other main surface of the pyroelectric substrate, two counter electrodes having substantially the same shape as the light receiving electrode and facing the light receiving electrode are arranged, and the other main surface of the pyroelectric substrate is arranged. Mounting electrodes for external connection are provided at both ends of the counter electrode, and the counter electrode and the mount electrode are connected by a lead electrode having a width narrower than that of the counter electrode.
【０００７】[0007]
【作用】焦電基板の裏面に配設された対向電極が、焦電
基板の一方の主面に配設された受光電極と略同一の形状
に形成され、上記受光電極と対向する位置に配設されて
いるとともに、取付電極が焦電基板の裏面の両端側に配
設され、かつ、対向電極と取付電極が対向電極よりも幅
の狭いリード電極により接続されているため、焦電基板
の裏面（他方の主面）に形成される電極全体の面積が、
前述の従来の焦電素子の裏面電極の面積と比べて小さく
なり、熱容量が減少するとともに、形成されるストレー
容量が小さくなり、素子全体としての静電容量（素子容
量）が減少して焦電素子の電圧感度が向上する。The counter electrode disposed on the back surface of the pyroelectric substrate is formed in a shape substantially the same as the light receiving electrode disposed on one main surface of the pyroelectric substrate, and is arranged at a position facing the light receiving electrode. Since the mounting electrodes are provided on both sides of the back surface of the pyroelectric substrate, and the counter electrode and the mounting electrode are connected by the lead electrodes that are narrower than the counter electrode, The area of the entire electrode formed on the back surface (the other main surface) is
Compared with the area of the back electrode of the conventional pyroelectric element described above, the heat capacity is reduced, and the stray capacitance that is formed is also reduced, so that the electrostatic capacitance (element capacitance) of the entire element is reduced and the pyroelectric element is reduced. The voltage sensitivity of the device is improved.
【０００８】[0008]
【実施例】以下、この発明の実施例を図に基づいて説明
する。この実施例の焦電型赤外線センサ用の焦電素子に
おいては、図２に示すように、焦電体（焦電基板）１０
の一方の主面（受光面）に２つの受光電極１ａ，１ｂが
配設され、この２つの受光電極１ａ，１ｂが接続電極５
により接続されている。そして、焦電基板１０の他方の
主面（裏面）には、図１に示すように、上記受光電極１
ａ及び１ｂと略同一の形状を有し、かつ、受光電極１
ａ，１ｂと対向する対向電極２ａ，２ｂが配設されてい
る。さらに、焦電基板１０の裏面の両端部には、外部の
素子（ＦＥＴなど）と電気的接続を行うための取付電極
３ａ，３ｂが配設されており、この取付電極３ａ，３ｂ
と上記対向電極２ａ及び２ｂがリード電極４ａ，４ｂに
より電気的に接続されている。Embodiments of the present invention will be described below with reference to the drawings. In the pyroelectric element for the pyroelectric infrared sensor of this embodiment, as shown in FIG. 2, the pyroelectric body (pyroelectric substrate) 10 is used.
Two light receiving electrodes 1a and 1b are arranged on one of the main surfaces (light receiving surface), and the two light receiving electrodes 1a and 1b are connected to the connection electrode 5.
Connected by. Then, on the other main surface (back surface) of the pyroelectric substrate 10, as shown in FIG.
a and 1b have substantially the same shape, and the light receiving electrode 1
Counter electrodes 2a and 2b facing a and 1b are provided. Further, mounting electrodes 3a and 3b for electrically connecting to an external element (FET or the like) are provided at both ends of the back surface of the pyroelectric substrate 10. The mounting electrodes 3a and 3b are provided.
And the counter electrodes 2a and 2b are electrically connected by lead electrodes 4a and 4b.
【０００９】このように、上記実施例の焦電素子は、焦
電基板１０の裏面に形成される電極の全体の面積が、図
５に示す従来の焦電素子の裏面電極（対向電極）の面積
より小さくなっている。As described above, in the pyroelectric element of the above-described embodiment, the total area of the electrodes formed on the back surface of the pyroelectric substrate 10 is the same as that of the back surface electrode (counter electrode) of the conventional pyroelectric element shown in FIG. It is smaller than the area.
【００１０】ところで、一般的に知られる焦電型赤外線
センサの出力電圧の評価方法としては、角周波数ωで変
調された入射赤外線エネルギーの実効値ＩWに対する出
力電圧の実効値Ｖ0の比で与えられる電圧感度ＲVの値の
大きさで評価する方法があり、電圧感度ＲVは、下記の
式(1)から求められる。By the way, as a method of evaluating the output voltage of a generally known pyroelectric infrared sensor, the ratio of the effective value V 0 of the output voltage to the effective value I W of the incident infrared energy modulated by the angular frequency ω is used. There is a method of evaluating the value of the given voltage sensitivity R V , and the voltage sensitivity R V is obtained from the following equation (1).
【００１１】 ＲV＝（η・ρ）／（ω・ＣV・ｔ・Ｃ） ……(1) 但し、η ：放射効率 ρ ：焦電係数 ＣV：熱容量 ｔ ：焦電素子の厚み Ｃ ：素子容量R V = (η · ρ) / (ω · C V · t · C) (1) where η: Radiation efficiency ρ: Pyroelectric coefficient C V : Heat capacity t: Pyroelectric element thickness C : Element capacity
【００１２】そして、上記実施例の焦電素子を、前述の
図４，５に示した従来の焦電素子と比較すると、放射効
率η，焦電係数ρ，角周波数ω，焦電素子の厚みｔは一
定であるが、熱容量ＣVと素子容量Ｃが異なる。Comparing the pyroelectric element of the above embodiment with the conventional pyroelectric elements shown in FIGS. 4 and 5, the radiation efficiency η, the pyroelectric coefficient ρ, the angular frequency ω, the thickness of the pyroelectric element. Although t is constant, the heat capacity C V and the element capacity C are different.
【００１３】まず、熱容量ＣVについて検討すると、従
来の焦電素子の裏面電極の面積を１とした場合に、上記
実施例の焦電基板の裏面に形成された電極の全面積は約
０．６８となり、電極の面積が小さくなる分だけ熱容量
ＣVも小さくなる。これを焦電素子全体で考えると、従
来の焦電素子の熱容量ＣVを１とした場合に、上記実施
例の焦電素子の熱容量ＣVは０．９８となる。First, considering the heat capacity C V , assuming that the area of the back surface electrode of the conventional pyroelectric element is 1, the total area of the electrodes formed on the back surface of the pyroelectric substrate of the above embodiment is about 0. As a result, the heat capacity C V becomes smaller as the area of the electrode becomes smaller. Considering this as the entire pyroelectric element, when the heat capacity C V of the conventional pyroelectric element is set to 1, the heat capacity C V of the pyroelectric element of the above embodiment is 0.98.
【００１４】次に、素子容量Ｃについて検討すると、従
来の焦電素子のストレー容量ＣSを１とした場合に、上
記実施例の焦電素子のストレー容量ＣSは０．４５とな
る。これを焦電素子全体の素子容量Ｃで考えると、従来
の焦電素子の素子容量Ｃを１とした場合に、上記実施例
の焦電素子の素子容量Ｃは０．９３となる。Next, considering the element capacitance C, when the stray capacitance C S of the conventional pyroelectric element is 1, the stray capacitance C S of the pyroelectric element of the above embodiment is 0.45. Considering this as the element capacitance C of the entire pyroelectric element, when the element capacitance C of the conventional pyroelectric element is set to 1, the element capacitance C of the pyroelectric element of the above embodiment is 0.93.
【００１５】したがって、上記実施例の電圧感度Ｒ
V1は、 ＲV1＝（η・ρ）／（０．９８×０．９３・ω・ＣV・ｔ・Ｃ） ≒１．１０×（η・ρ）／（ω・ＣV・ｔ・Ｃ） ＝１．１０ＲV となり、従来の焦電素子に比べて約１０％電圧感度が向
上することがわかる。Therefore, the voltage sensitivity R of the above embodiment is
V1 is R V1 = (η · ρ) / (0.98 × 0.93 · ω · C V · t · C) ≈1.10 × (η · ρ) / (ω · C V · t · C ) = 1.10R V , which means that the voltage sensitivity is improved by about 10% as compared with the conventional pyroelectric element.
【００１６】上記実施例における焦電基板の他方の主面
（裏面）の電極の形状は、あくまでもこの発明の一実施
例に過ぎず、この発明の焦電基板の裏面に形成される取
付電極やリード電極などの具体的形状は、上記実施例の
形状に限定されるものではなく、この発明の効果を損わ
ない範囲において、種々の形状に形成することが可能で
ある。したがって、電圧感度ＲVは、上記実施例の値と
は異なる値をとる場合があるが、いずれにしても、従来
の焦電素子と比べて焦電基板の裏面に形成される電極全
体の面積を減少させることが可能であり、熱容量及び静
電容量（素子容量）を低減して電圧感度を向上させるこ
とができる。The shape of the electrode on the other main surface (rear surface) of the pyroelectric substrate in the above embodiment is merely one embodiment of the present invention, and the mounting electrodes formed on the back surface of the pyroelectric substrate of the present invention and The specific shape of the lead electrode and the like is not limited to the shape of the above-described embodiment, and various shapes can be formed within the range that does not impair the effects of the present invention. Therefore, the voltage sensitivity R V may take a value different from the value in the above-described embodiment, but in any case, the area of the entire electrode formed on the back surface of the pyroelectric substrate is larger than that of the conventional pyroelectric element. It is possible to reduce the heat capacity and the electrostatic capacity (element capacity) and improve the voltage sensitivity.
【００１７】[0017]
【発明の効果】上述のように、この発明の焦電素子は、
焦電基板の受光面に配設された受光電極と略同一の形状
を有する対向電極を、焦電基板の裏面（他方の主面）
の、上記受光電極と対向する位置に配設するとともに、
焦電基板の裏面の両端側に取付電極を配設し、かつ、対
向電極と取付電極とを対向電極よりも幅の狭いリード電
極により接続するようにしているので、焦電基板の裏面
に形成される電極全体の面積が減少し、熱容量が小さく
なるとともに、ストレー容量の形成が抑制され、素子全
体としての静電容量（素子容量）が減少して焦電素子の
電圧感度が向上する。As described above, the pyroelectric element of the present invention is
The counter electrode having substantially the same shape as the light receiving electrode disposed on the light receiving surface of the pyroelectric substrate is provided on the back surface (the other main surface) of the pyroelectric substrate.
In addition to being disposed at a position facing the light receiving electrode,
Since the mounting electrodes are arranged on both ends of the back surface of the pyroelectric substrate and the counter electrode and the mounting electrode are connected by the lead electrodes having a width narrower than that of the counter electrode, the electrodes are formed on the back surface of the pyroelectric substrate. As a result, the area of the entire electrode is reduced, the heat capacity is reduced, the formation of stray capacitance is suppressed, the electrostatic capacitance (element capacitance) of the entire element is reduced, and the voltage sensitivity of the pyroelectric element is improved.
【図１】この発明の一実施例にかかる焦電素子の他方の
主面（受光面の裏面）を示す図である。FIG. 1 is a diagram showing the other principal surface (rear surface of a light receiving surface) of a pyroelectric element according to an embodiment of the present invention.
【図２】この発明の一実施例にかかる焦電素子の受光面
を示す図である。FIG. 2 is a diagram showing a light receiving surface of a pyroelectric element according to an embodiment of the present invention.
【図３】焦電型赤外線センサの構成を示す分解斜視図で
ある。FIG. 3 is an exploded perspective view showing a configuration of a pyroelectric infrared sensor.
【図４】従来の焦電素子の受光面を示す図である。FIG. 4 is a diagram showing a light receiving surface of a conventional pyroelectric element.
【図５】従来の焦電素子の他方の主面（受光面の裏面）
を示す図である。FIG. 5 is the other main surface of the conventional pyroelectric element (rear surface of the light receiving surface).
FIG.
１ａ，１ｂ 受光電極 ２ａ，２ｂ 対向電極 ３ａ，３ｂ 取付電極 ４ａ，４ｂ リード電極 １０ 焦電基板 1a, 1b Light receiving electrode 2a, 2b Counter electrode 3a, 3b Mounting electrode 4a, 4b Lead electrode 10 Pyroelectric substrate
Claims (1)
接続電極により接続された２つの受光電極を配設し、焦
電基板の他方の主面に、前記受光電極と略同一の形状を
有し、前記受光電極と対向する２つの対向電極を配設す
るとともに、焦電基板の他方の主面の両端部に外部接続
用の取付電極を配設し、前記対向電極と前記取付電極と
を前記対向電極より幅の狭いリード電極により接続した
ことを特徴とする焦電素子。1. A light receiving surface, which is one main surface of a pyroelectric substrate,
Two light receiving electrodes connected by connection electrodes are provided, and two counter electrodes having substantially the same shape as the light receiving electrodes and facing the light receiving electrodes are provided on the other main surface of the pyroelectric substrate. In addition, mounting electrodes for external connection are arranged at both ends of the other main surface of the pyroelectric substrate, and the counter electrode and the mounting electrode are connected by a lead electrode having a width narrower than that of the counter electrode. And a pyroelectric element.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4021918A JPH05187918A (en) | 1992-01-09 | 1992-01-09 | Pyroelectric element |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4021918A JPH05187918A (en) | 1992-01-09 | 1992-01-09 | Pyroelectric element |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH05187918A true JPH05187918A (en) | 1993-07-27 |
Family
ID=12068461
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4021918A Pending JPH05187918A (en) | 1992-01-09 | 1992-01-09 | Pyroelectric element |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH05187918A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102822646A (en) * | 2011-02-24 | 2012-12-12 | 日本碍子株式会社 | Pyroelectric element and manufacturing method therefor |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0227530B2 (en) * | 1982-04-16 | 1990-06-18 | Horton Ind | |
| JPH04293277A (en) * | 1991-03-22 | 1992-10-16 | Horiba Ltd | Pyroelectric infrared detector |
| JPH04346037A (en) * | 1991-05-24 | 1992-12-01 | Daishinku Co | Pyroelectric type infrared-ray sensor |
-
1992
- 1992-01-09 JP JP4021918A patent/JPH05187918A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0227530B2 (en) * | 1982-04-16 | 1990-06-18 | Horton Ind | |
| JPH04293277A (en) * | 1991-03-22 | 1992-10-16 | Horiba Ltd | Pyroelectric infrared detector |
| JPH04346037A (en) * | 1991-05-24 | 1992-12-01 | Daishinku Co | Pyroelectric type infrared-ray sensor |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102822646A (en) * | 2011-02-24 | 2012-12-12 | 日本碍子株式会社 | Pyroelectric element and manufacturing method therefor |
| CN102822646B (en) * | 2011-02-24 | 2014-12-17 | 日本碍子株式会社 | Pyroelectric element and manufacturing method therefor |
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