JPH0614077B2 - Surface potential detector - Google Patents
Surface potential detectorInfo
- Publication number
- JPH0614077B2 JPH0614077B2 JP608986A JP608986A JPH0614077B2 JP H0614077 B2 JPH0614077 B2 JP H0614077B2 JP 608986 A JP608986 A JP 608986A JP 608986 A JP608986 A JP 608986A JP H0614077 B2 JPH0614077 B2 JP H0614077B2
- Authority
- JP
- Japan
- Prior art keywords
- measured
- output
- detection
- surface potential
- distance
- Prior art date
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- Expired - Lifetime
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Description
【発明の詳細な説明】 ［産業上の利用分野］ この発明は、非接触に物体の表面電位を検出する装置に
関し、特に被測定表面と検出装置との間の設定距離の変
動に起因する出力変動を低減する構造を備えた表面電位
検出装置に関する。Description: TECHNICAL FIELD The present invention relates to a device for detecting the surface potential of an object in a non-contact manner, and particularly to an output caused by a change in a set distance between a surface to be measured and a detection device. The present invention relates to a surface potential detecting device having a structure for reducing fluctuation.
［従来の技術］ 非接触に被測定表面の電位を検出する装置としては、チ
ョッパ式のものあるいは振動容量型のものなどが周知で
ある。いずれの形式の検出装置も、被測定表面と検知電
極との間に形成される電気力線の数を変化させ、検知電
極上に誘起される電荷の変動に基づき、その表面電位を
検出するものである。したがって、被測定表面と検出装
置との間の距離が変動すると、電気力線の数が変動し、
その結果検出装置の出力が変化することを避けることは
できなかった。[Prior Art] As a device for non-contactly detecting the potential of the surface to be measured, a chopper type device or a vibration capacitance type device is well known. In any type of detection device, the number of electric lines of force formed between the surface to be measured and the detection electrode is changed, and the surface potential is detected based on the fluctuation of the electric charge induced on the detection electrode. Is. Therefore, when the distance between the surface to be measured and the detection device changes, the number of lines of electric force changes,
As a result, it was unavoidable that the output of the detector changed.
そこで、従来より、上記被測定表面との間の距離の変動
に基づく出力変化を補正するために、種々の補正手段が
提案されている。Therefore, conventionally, various correction means have been proposed in order to correct the output change based on the change in the distance from the surface to be measured.
特開昭５６−４０６２号は、その一例を開示している。
すなわち、第７図に示すように、被測定表面１と検知電
極２との間に形成される電気力線を周期的にチョッピン
グするチョッパ３を有するチョッパ型の表面電位検出装
置において、第８図に示すように、チョッパ３自体に測
定出力に比例した高電圧をフィードバックし、上記距離
依存性を減少させる構成が示されている。Japanese Unexamined Patent Publication No. 56-4062 discloses one example.
That is, as shown in FIG. 7, in a chopper type surface potential detecting device having a chopper 3 for periodically chopping the lines of electric force formed between the surface to be measured 1 and the detection electrode 2, FIG. As shown in FIG. 5, a configuration is shown in which a high voltage proportional to the measurement output is fed back to the chopper 3 itself to reduce the distance dependency.
また、特開昭６０−１５２９５９号には、第９図に示す
ように、被測定表面１との間の距離の異なる第１および
第２の検知電極６，７を設け、各検知電極６，７の出力
の差をとり、該出力差に基づいて測定出力を補正する構
成が開示されている。Further, in JP-A-60-152959, as shown in FIG. 9, first and second detection electrodes 6 and 7 having different distances from the surface to be measured 1 are provided, and each detection electrode 6, A configuration is disclosed in which the difference between the outputs of 7 is taken and the measurement output is corrected based on the difference of the outputs.
［発明が解決しようとする問題点］ しかしながら、特開昭５６−４０６２号に開示された構
成では、チョッパに高電圧をフィードバックする必要が
あるため、高電圧発生手段やチョッパの絶縁構造が必要
となり、装置全体の構成が極めて複雑となりかつ小形化
が困難であるという問題があった。[Problems to be Solved by the Invention] However, in the configuration disclosed in Japanese Patent Laid-Open No. 56-4062, since it is necessary to feed back a high voltage to the chopper, a high voltage generating means and an insulating structure of the chopper are required. However, there has been a problem that the configuration of the entire apparatus becomes extremely complicated and it is difficult to reduce the size.
また、特開昭６０−１５２９５９号に開示されているよ
うに被測定表面との対向距離の異なる２種の検知電極
６，７を配置した構成では、下記のような問題があっ
た。Further, as disclosed in Japanese Patent Laid-Open No. 60-152959, the structure in which two types of detection electrodes 6 and 7 having different facing distances to the surface to be measured are arranged has the following problems.
第９図に示されているように、ここではケース８に被測
定表面１から電気力線Ｘを導くために一定形状の窓部８
ａが形成されている。すなわち検知電極は複数設けられ
ているが窓部８ａは単一であり、したがって第１０図に
模式的に示すように、同一の窓部８ａを介して電気力線
Ｘが検知電極６，７に至ることになる。As shown in FIG. 9, here, in order to guide the lines of electric force X from the surface to be measured 1 to the case 8, the window 8 having a constant shape is used.
a is formed. That is, although a plurality of detection electrodes are provided, the window portion 8a is single. Therefore, as schematically shown in FIG. 10, the lines of electric force X are applied to the detection electrodes 6 and 7 through the same window portion 8a. Will be reached.
同様の構成は、振動容量型の表面電位検出装置において
も可能であり、たとえば第１１図に模式的に示すよう
に、被測定表面１との間の距離が異なるように第１およ
び第２の検知電極１１，１２を設けることにより、各検
知電極１１，１２の出力差に基づき検出出力を補正する
ことができると考えられる。A similar configuration is also possible in a vibration capacitance type surface potential detecting device. For example, as schematically shown in FIG. 11, the first and second devices are arranged so that the distance to the measured surface 1 is different. It is considered that the detection output can be corrected based on the output difference between the detection electrodes 11 and 12 by providing the detection electrodes 11 and 12.
しかしながら実際には、被測定表面との対向距離の異な
る検知電極６，７あるいは１１，１２を備えた表面電位
検出装置では、２個の検知電極より得られる出力の差は
やはり距離の関数となっており、したがって、２個の検
知電極の差を取る方法では距離補正された出力を得るこ
とができないのは明らかである。すなわち、第１２図に
示すように、検知電極１１の出力と検知電極１２の出力
差は一定とならない。However, in reality, in the surface potential detecting device including the sensing electrodes 6, 7 or 11, 12 having different facing distances from the surface to be measured, the difference between the outputs obtained from the two sensing electrodes is still a function of the distance. Therefore, it is obvious that the distance-corrected output cannot be obtained by the method of taking the difference between the two sensing electrodes. That is, as shown in FIG. 12, the output difference between the detection electrode 11 and the detection electrode 12 is not constant.
一方、２つの検知電極６，７あるいは１１，１２の出力
の比を取り、この比の値が距離の関数となることを利用
して２つの電極の出力の一方を補正して、距離依存性を
持たない検知出力を得る方法が出願されている。On the other hand, taking the ratio of the outputs of the two sensing electrodes 6, 7 or 11, 12 and correcting the one of the outputs of the two electrodes by utilizing the fact that the value of this ratio is a function of the distance, A method has been filed for obtaining a detection output that does not have a.
しかしながら、この方法においても、実際には、被測定
表面との対向距離の異なる検知電極６，７あるいは１
１，１２を備えた表面電位検出装置では、２個の検知電
極より得られる出力の比の変化量は極めて少なく、した
がって距離補正に必要なデータを得ることは困難である
ことがわかった。すなわち、第１１図に模式図で示した
ような振動容量型の表面電位検出装置を例にとると、第
１２図に示すように、各検知電極と被測定表面１との間
の距離を異ならせても、各検知電極１１，１２より得ら
れる出力の比はほとんど変化しないことがわかった。な
お、第１３図に、第１２図の測定に用いた構造において
各検知電極と被測定表面間の距離を等しく構成したもの
についてのデータを示す。第１２図および第１３図の結
果を比較することにより、検知電極１１，１２の出力比
の値こそ異なっているが、被測定表面と検出装置との間
の距離が変化しても該出力比の値は各図においてほとん
ど同じであることに変わりないことがわかる。すなわ
ち、２個の検知電極１１，１２を被測定表面から異なる
距離に配置した効果はほとんど現われていないことがわ
かる。However, even in this method, the sensing electrodes 6, 7 or 1 having different facing distances from the surface to be measured are actually used.
It has been found that in the surface potential detecting device provided with Nos. 1 and 12, the amount of change in the ratio of the outputs obtained from the two detection electrodes is extremely small, and therefore it is difficult to obtain the data necessary for distance correction. That is, taking the vibration capacitance type surface potential detecting device as shown in the schematic view of FIG. 11 as an example, as shown in FIG. 12, if the distance between each sensing electrode and the surface 1 to be measured is different. Even if it did, it was found that the ratio of the outputs obtained from the detection electrodes 11 and 12 hardly changed. Note that FIG. 13 shows data on the structure used for the measurement of FIG. 12 in which the distance between each sensing electrode and the surface to be measured is made equal. By comparing the results of FIGS. 12 and 13, the values of the output ratios of the detection electrodes 11 and 12 are different, but even if the distance between the surface to be measured and the detection device is changed, the output ratio is changed. It can be seen that the value of is almost the same in each figure. That is, it can be seen that the effect of arranging the two detection electrodes 11 and 12 at different distances from the surface to be measured hardly appears.
このことは、第９図に示したチョッパ型の表面電位検出
装置においてもあてはまり、したがって導電性ケース８
内で第１および第２の検知電極６，７あるいは１１，１
２をずらして配置したとしても、このような複数の検知
電極の出力に基づいて、被測定表面と表面電位検出装置
との間の設定距離の変動に基づく出力変動を補正するこ
とができないことがわかる。This also applies to the chopper type surface potential detecting device shown in FIG.
In which the first and second sensing electrodes 6,7 or 11,1
Even if 2 is arranged in a staggered manner, it is not possible to correct the output fluctuation based on the fluctuation of the set distance between the surface to be measured and the surface potential detecting device based on the outputs of the plurality of sensing electrodes. Recognize.
よって、この発明の目的は、複雑な構造を要することな
く、被測定表面との間の設定距離の変動に基づく出力変
動を効果的に低減し得る構造を備えた表面電位検出装置
を提供することにある。Therefore, an object of the present invention is to provide a surface potential detecting device having a structure capable of effectively reducing output fluctuations due to fluctuations in the set distance from the surface to be measured without requiring a complicated structure. It is in.
［問題点を解決するための手段］ この発明の表面電位検出装置は、非接触に物体の表面電
位を検出するための装置であり、チョッパ型および振動
容量型のいずれにも適用されるものである。[Means for Solving Problems] The surface potential detecting device of the present invention is a device for detecting the surface potential of an object in a non-contact manner, and is applied to both a chopper type and a vibration capacitance type. is there.
そして、この発明においても、被測定表面から所定距離
を隔てて配置され、被測定表面の電位に応じて電荷が表
面に誘起されるように構成された第１および第２の検知
電極が備えられている。また、第１および第２の検知電
極を収納する導電性ケースが備えられているが、このケ
ースには、各検知電極に被測定表面よりの電気力線を入
射させるための第１および第２の窓部が、それぞれの検
知電極に対応して形成されている。さらに、この第１お
よび第２の窓部は、被測定表面との間の距離が異なるよ
うにずらされて形成されている。そして、第１および第
２の検知電極は同一平面上に設置されていても何ら不都
合は生じない。Also in the present invention, the first and second detection electrodes that are arranged at a predetermined distance from the surface to be measured and that are configured to induce charges on the surface according to the potential of the surface to be measured are provided. ing. Further, a conductive case for accommodating the first and second detection electrodes is provided, and in this case, the first and second electrically conductive lines for causing the lines of electric force from the surface to be measured to enter each detection electrode. Windows are formed corresponding to the respective detection electrodes. Further, the first and second windows are formed so as to be displaced so that the distance to the surface to be measured is different. Then, even if the first and second detection electrodes are installed on the same plane, no inconvenience occurs.
さらに、第１および第２の検知電極上に誘起された電荷
を電圧信号として取出す第１および第２の検出手段と、
第１および第２の検出手段の出力の比をとり、該比に基
づいて第１または第２の検出手段の出力を補正する補正
手段とを備える。Furthermore, first and second detection means for extracting the charges induced on the first and second detection electrodes as a voltage signal,
Compensation means for taking a ratio of the outputs of the first and second detection means and compensating the output of the first or second detection means based on the ratio.
［この発明の表面電位検出装置における補正原理］ 上述したように、振動容量型およびチョッパ型のいずれ
の表面電位検出装置においても、導電性ケース内に被測
定表面からの距離が異なるように２つの検知電極を配置
し、各検知電極の出力差や出力比に基づいて検出装置の
被測定表面との間の設定距離の変動に基づく出力変動を
補正することはできなかった。[Principle of Correction in Surface Potential Detection Device of the Present Invention] As described above, in both the vibrating capacitance type and the chopper type surface potential detection device, two distances from the surface to be measured are different in the conductive case. It was not possible to arrange the detection electrodes and correct the output variation based on the variation in the set distance between the detection device and the surface to be measured based on the output difference or the output ratio of the detection electrodes.
そこで、今、第１２図および第１３図の結果を再度考察
すると、表面電位検出装置と被測定表面との間の距離が
変化しても、両検知電極の出力比がほぼ一定であるとい
うこと（両検知電極をずらせて配置したとしても）は、
ケース窓部より後方にすなわちケース窓部から遠ざけて
検知電極を設置したとしても、検知電極の出力にはほと
んど影響を及ぼさないことを意味する。Therefore, considering the results of FIGS. 12 and 13 again, it can be seen that the output ratios of both detection electrodes are substantially constant even if the distance between the surface potential detecting device and the surface to be measured changes. (Even if both sensing electrodes are arranged in a staggered manner),
This means that even if the detection electrode is installed behind the case window, that is, away from the case window, the output of the detection electrode is hardly affected.
これに対して、この発明では、被測定表面と検知電極と
の間に形成される、すなわちケースの窓部を介して検知
電極に入射する電気力線の数は、被測定表面とケース窓
部との位置関係に影響されるものことを考慮し、第１お
よび第２の検知電極のそれぞれに対して窓部を設け、か
つこの第１および第２の窓部と被測定表面との間の距離
が異なるように各窓部をずらせて形成したものである。On the other hand, in the present invention, the number of lines of electric force formed between the surface to be measured and the detection electrode, that is, incident on the detection electrode through the window portion of the case, is determined by the number of the surface to be measured and the window portion of the case. In consideration of the influence of the positional relationship between the first and second detection electrodes, a window is provided for each of the first and second sensing electrodes, and the window between the first and second windows and the surface to be measured is provided. It is formed by shifting the windows so that the distances are different.
第１および第２の窓部が上述のようにずらされて配置さ
れているので、この発明においては第１および第２の検
知電極により得られる出力の大きさは異なり、また被測
定表面と表面電位検出装置との間の設定距離の変動に伴
なう両検知電極の出力の変化の割合も異なるものにな
る。したがって、第１および第２の検知電極の出力の比
をとることにより、被測定表面−表面電位検出装置間の
距離変動に応じた距離補正用出力を得ることができる。Since the first and second windows are arranged so as to be displaced as described above, the magnitudes of the outputs obtained by the first and second sensing electrodes are different in the present invention, and the measured surface and the surface are different. The rate of change in the output of both detection electrodes due to the change in the set distance from the potential detecting device also becomes different. Therefore, by taking the ratio of the outputs of the first and second detection electrodes, it is possible to obtain the distance correction output according to the distance variation between the surface to be measured and the surface potential detecting device.
すなわち、従来例では検知電極に入射する電気力線は、
被測定表面と検知電極面との間の距離により決定される
と考えられていたのに対し、本発明では、被測定表面と
ケースに設けられた窓部との位置関係により検知電極に
入射する電気力線の数が決定されるという考えに基づく
ものである。That is, in the conventional example, the line of electric force incident on the detection electrode is
While it was considered that it was determined by the distance between the surface to be measured and the surface of the detection electrode, in the present invention, the light is incident on the detection electrode due to the positional relationship between the surface to be measured and the window provided on the case. It is based on the idea that the number of lines of electric force is determined.
［実施例の説明］ 第１図は、振動容量型表面電位検出装置についてのこの
発明の一実施例を示す断面図である。導電性ケース２１
内に、第１の検知電極２３および第２の検知電極２４が
収納されている。各検知電極２３，２４は、第３図に示
すように、フレキシブル基板２５上に形成されている。
該フレキシブル基板２５は、たとえばシリコン接着剤に
より振動手段としての圧電音叉２６の片脚に接着されて
いる。圧電音叉２６は、支持部材２７を介して絶縁基板
２８に固定されている。[Description of Embodiments] FIG. 1 is a sectional view showing an embodiment of the present invention with respect to a vibration capacitance type surface potential detecting device. Conductive case 21
A first detection electrode 23 and a second detection electrode 24 are housed inside. Each of the detection electrodes 23 and 24 is formed on a flexible substrate 25, as shown in FIG.
The flexible substrate 25 is adhered to one leg of a piezoelectric tuning fork 26 as a vibrating means by, for example, silicon adhesive. The piezoelectric tuning fork 26 is fixed to an insulating substrate 28 via a support member 27.
他方、導電性ケース２１には、各検知電極２３，２４に
対応して、第１の窓部３１および第２の窓部３２が形成
されている。そして、この各窓部３１，３２は、第１図
および第１図の要部を拡大して示す第２図から明らかな
ように、距離ｇだけずらされて形成されている。したが
って、被測定表面１との間の距離ｄ１，ｄ２も｜ｄ１−
ｄ２｜＝ｇの関係にある。この距離ｇは、各窓部３１，
３２をたとえば３．４×３．５mm程度の大きさとした場
合、約１．０mm程度に選ばれる。On the other hand, the conductive case 21 is formed with a first window portion 31 and a second window portion 32 corresponding to the detection electrodes 23 and 24. The windows 31 and 32 are formed so as to be displaced by a distance g, as is apparent from FIG. 2 and FIG. 2 which is an enlarged view of the main parts of FIG. Therefore, the distances d 1 and d 2 from the surface to be measured 1 are also | d 1 −
There is a relationship of d 2 | = g. This distance g is
If 32 has a size of, for example, about 3.4 × 3.5 mm, it is selected to be about 1.0 mm.
絶縁基板２８は、第４図に示すように、その両面に適宜
の電子部品が実装されており、該基板２８上に各検知電
極２３，２４上に生じた電荷を取出すための検出手段お
よび各検知電極２３，２４の検出出力の比により被測定
表面−表面電位検出装置間の設定距離に基づく出力変動
を補正する補正手段が構成されている。As shown in FIG. 4, the insulating substrate 28 has appropriate electronic components mounted on both surfaces thereof, and a detection unit for extracting charges generated on the detection electrodes 23, 24 on the substrate 28 and each of them. A correction unit is configured to correct the output fluctuation based on the set distance between the surface to be measured and the surface potential detection device based on the ratio of the detection outputs of the detection electrodes 23 and 24.
第５図は、第１図に示した実施例の表面電位検出装置の
概略ブロック図である。第１の検知電極２３および第２
の検知電極２４には、それぞれ、基準電位（この実施例
ではグラウンド電位）との間に電流−電圧変換用抵抗４
１，４２が接続されている。この抵抗４１，４２は、検
知電極２３，２４の表面に誘起される電荷を電圧として
取出すための第１および第２の検出手段の一部を構成す
るものである。この検出手段は、第１の検知電極２３側
においては、抵抗４１のほか、その後段に接続されるイ
ンピーダンス変換回路４３，バンドパスフィルタ／増幅
回路４５および整流・平滑・増幅回路４７を含む。同様
に、第２の検知電極２４側においても、抵抗４２の後段
に、順次、インピーダンス変換回路４４，バンドパスフ
ィルタ／増幅回路４６および整流・平滑・増幅回路４８
が接続されている。FIG. 5 is a schematic block diagram of the surface potential detecting device of the embodiment shown in FIG. First sensing electrode 23 and second
Each of the detection electrodes 24 has a current-voltage conversion resistor 4 between it and the reference potential (the ground potential in this embodiment).
1, 42 are connected. The resistors 41 and 42 form part of the first and second detecting means for taking out the charges induced on the surfaces of the detection electrodes 23 and 24 as a voltage. On the first detection electrode 23 side, this detection means includes, in addition to the resistor 41, an impedance conversion circuit 43, a bandpass filter / amplification circuit 45, and a rectification / smoothing / amplification circuit 47 connected to the subsequent stage. Similarly, also on the second detection electrode 24 side, the impedance conversion circuit 44, the bandpass filter / amplification circuit 46, and the rectification / smoothing / amplification circuit 48 are sequentially provided in the subsequent stage of the resistor 42.
Are connected.
さらに、この実施例では、第１の検知電極２３に基づく
出力を測定出力とするために、一方の整流・平滑・増幅
回路４７の出力側に増幅回路４９が接続されている。ま
た、上述した補正原理に基づき補正を行なうための補正
手段として、割算／掛算回路５１および減算・増幅回路
５２が各整流・平滑・増幅回路４７，４８の後段に接続
されている。すなわち、一方の整流・平滑・増幅回路４
７の出力Ｖ１は分割され、増幅回路４９のほか割算／掛
算回路５１にも与えられる。Further, in this embodiment, an amplifying circuit 49 is connected to the output side of one of the rectifying / smoothing / amplifying circuits 47 in order to use the output based on the first detection electrode 23 as the measurement output. Further, as correction means for performing correction based on the above-described correction principle, the division / multiplication circuit 51 and the subtraction / amplification circuit 52 are connected to the subsequent stages of the rectification / smoothing / amplification circuits 47 and 48. That is, one rectifying / smoothing / amplifying circuit 4
The output V 1 of 7 is divided and applied to not only the amplifier circuit 49 but also the division / multiplication circuit 51.
また、割算／掛算回路５１には他方の整流・平滑・増幅
回路４８の出力Ｖ２すなわち第２の検知電極２４由来の
出力が与えられる。割算／掛算回路５１は、この両整流
・平滑・増幅回路４７，４８より与えられた出力Ｖ１，
Ｖ２の比をとり、かつ増幅回路４９より与えられた出力
Ｖ３を掛け合わせ、Ｖ４＝（１−Ｖ１／Ｖ２）×Ｖ３を
出力する。そして、この補正出力Ｖ４が減算・増幅回路
５２に与えられる。減算・増幅回路５２には、増幅回路
４９の出力Ｖ３も与えられる。この減算・増幅回路５２
は、測定出力Ｖ３から、補正出力Ｖ４を減算し、かつ増
幅し、出力端子５３に被測定表面−表面電位検出装置間
の距離の変動に依存しない測定出力を与える。The output V 2 of the other rectifying / smoothing / amplifying circuit 48, that is, the output from the second detection electrode 24 is given to the division / multiplication circuit 51. The division / multiplication circuit 51 outputs the output V 1 given by the rectification / smoothing / amplification circuits 47 and 48.
The ratio of V 2 is calculated, and the output V 3 given from the amplifier circuit 49 is multiplied to output V 4 = (1-V 1 / V 2 ) × V 3 . Then, the corrected output V 4 is given to the subtraction / amplification circuit 52. The subtraction / amplification circuit 52 is also supplied with the output V 3 of the amplification circuit 49. This subtraction / amplification circuit 52
Subtracts and amplifies the correction output V 4 from the measurement output V 3 and gives the output terminal 53 a measurement output that does not depend on the variation in the distance between the surface to be measured and the surface potential detecting device.
なお、第１の検知電極２３および第２の検知電極２４
は、第１図に示したように圧電音叉２６に固定されてお
り、第５図の圧電音叉発振回路６１は、この圧電音叉２
６を励振するために設けられているものである。Note that the first detection electrode 23 and the second detection electrode 24
Is fixed to the piezoelectric tuning fork 26 as shown in FIG. 1, and the piezoelectric tuning fork oscillation circuit 61 of FIG.
6 is provided for exciting.
上述したように、ケース窓部３１，３２がずらされて配
置されているので、第１および第２の検知電極２３，２
４より得られる出力の大きさは異なり、また被測定表面
と表面電位検出装置間の設定距離の変動により生じる検
出出力の変動の値も異なることになる。したがって、各
検知電極２３，２４の出力の比をとることにより、距離
変動に応じた距離補正用出力を得ることができる。As described above, since the case windows 31 and 32 are arranged so as to be displaced from each other, the first and second detection electrodes 23 and 2 are
4, the magnitude of the output obtained is different, and the value of the fluctuation of the detected output caused by the fluctuation of the set distance between the surface to be measured and the surface potential detecting device is also different. Therefore, by taking the ratio of the outputs of the detection electrodes 23 and 24, it is possible to obtain the output for distance correction according to the distance variation.
次に具体的な実験結果につき説明する。各検知電極より
得られる信号は、被測定表面と第１の窓部３２間の距離
が３．０mmのとき、それぞれ表面電位１００Ｖあたり約
０．５ｍＶrmsの正弦波である。周波数は、圧電音叉２
６の振動周波数と等しく、この例では８００Hzである。
増幅された検出信号の表面電位１００Ｖあたりの値およ
び整流されたそれぞれの検出信号により得られる距離補
正用出力の値を第６図に示す。Next, specific experimental results will be described. The signal obtained from each detection electrode is a sine wave of about 0.5 mV rms per 100 V of surface potential when the distance between the surface to be measured and the first window portion 32 is 3.0 mm. Frequency is piezoelectric tuning fork 2
It is equal to the vibration frequency of 6, which is 800 Hz in this example.
FIG. 6 shows the value of the amplified detection signal per surface potential of 100 V and the value of the output for distance correction obtained by each rectified detection signal.
第６図から明らかなように、被測定表面−表面電位検出
装置（ここでは第２の窓部３２を基準とした）の距離が
２〜４mmの間では、出力比が大きく変化していることが
わかる。よって、得られた距離補正出力を適当倍して、
いずれか一方の検知電極２３，２４由来の出力の一方に
加算または減算することにより、被測定表面−表面電位
検出装置間の設定距離の変動に依存しない出力の得られ
ることがわかる。As is apparent from FIG. 6, the output ratio greatly changes when the distance between the surface to be measured and the surface potential detecting device (here, the second window 32 is used as a reference) is 2 to 4 mm. I understand. Therefore, multiply the obtained distance correction output appropriately,
It can be seen that by adding or subtracting to one of the outputs derived from either one of the detection electrodes 23 and 24, an output that does not depend on the variation in the set distance between the surface to be measured and the surface potential detecting device can be obtained.
なお、加算・減算は、両検知電極２３，２４の出力比を
とる場合に、いずれの検知電極由来の出力を分母とする
かによって異なる。第５図に示した例では、第２の検知
電極２４の出力を分母としたため、第１の検知電極２３
由来の測定出力から、補正出力Ｖ４を減算したものであ
るが、逆に第１の検知電極由来の出力Ｖ１を分母として
比をとった場合には加算することになる。Note that the addition / subtraction differs depending on which detection electrode output is used as the denominator when the output ratio of both detection electrodes 23, 24 is taken. In the example shown in FIG. 5, since the output of the second detection electrode 24 is used as the denominator, the first detection electrode 23
The correction output V 4 is subtracted from the derived measurement output, but on the contrary, when the ratio is taken with the output V 1 derived from the first detection electrode as the denominator, it is added.
なお、上述した実施例では、検知電極２３，２４は、同
一圧電音叉２６に固定されていたが、別体の圧電音叉に
固定されていてもよい。この場合には、２つの電極の出
力比をそれぞれの出力を整流した後に行う。また、検知
電極を振動させる振動手段としては、圧電音叉に限ら
ず、Ｉ字状あるいはＨ字状の圧電音片を用いてもよく、
また電磁振動子を用いてもよい。Although the detection electrodes 23 and 24 are fixed to the same piezoelectric tuning fork 26 in the above-described embodiments, they may be fixed to separate piezoelectric tuning forks. In this case, the output ratio of the two electrodes is obtained after rectifying the respective outputs. The vibrating means for vibrating the detection electrode is not limited to the piezoelectric tuning fork, and an I-shaped or H-shaped piezoelectric tuning piece may be used.
Alternatively, an electromagnetic vibrator may be used.
さらに、この発明は、振動容量型の表面電位検出装置だ
けでなく、チョッパを用いたチョッパ型の表面電極検出
装置においても同様に適用することができる。Further, the present invention can be applied not only to the vibration capacitance type surface potential detecting device but also to a chopper type surface electrode detecting device using a chopper.
［発明の効果］ この発明では、第１および第２の検知電極に対応して、
ケースに第１の窓部および第２の窓部が形成されてお
り、かつこの第１の窓部および第２の窓部は、被測定表
面との間の距離が異なるように形成されている。そし
て、各検知電極の出力比を求めそれによって測定出力を
補正する補正手段が設けられているので、被測定表面と
表面電位検出装置との間の設定距離の変動に影響されな
い出力を得ることが可能となる。よって、表面電位検出
装置使用時に、被測定表面に対しての煩雑な位置決め調
整作業を解消することができる。のみならず、この発明
の表面電位検出装置では、検知電極に接続される複雑な
補正回路を要しないので、表面電位検出装置の大きさ、
特に検知電極部分の大きさを大きくすることもない。そ
れゆえに、たとえば複写機の感光ドラム近傍等の狭いス
ペースにも簡単に取付けることができる。[Effect of the Invention] In the present invention, the first and second detection electrodes are provided in correspondence with each other.
A first window portion and a second window portion are formed in the case, and the first window portion and the second window portion are formed so that the distance from the surface to be measured is different. . Further, since the correction means for determining the output ratio of each detection electrode and correcting the measured output by the output ratio is provided, it is possible to obtain an output that is not affected by the variation in the set distance between the surface to be measured and the surface potential detecting device. It will be possible. Therefore, when using the surface potential detecting device, it is possible to eliminate a complicated positioning adjustment work for the surface to be measured. In addition, the surface potential detection device of the present invention does not require a complicated correction circuit connected to the detection electrode, so that the size of the surface potential detection device is
In particular, the size of the detection electrode portion is not increased. Therefore, it can be easily installed in a narrow space such as near the photosensitive drum of a copying machine.
第１図は、この発明の一実施例の表面電位検出装置を示
す断面図である。第２図は、第１図の表面電位検出装置
の要部を拡大して示す断面図である。第３図は、第１図
に示した実施例において用いる検知電極の配置を示す平
面図である。第４図は、第１図に示した実施例において
用いられている絶縁基板および該基板上に実装された電
子部品を示す平面図である。第５図は、第１図に示した
実施例の回路部分の概略ブロック図である。第６図は、
この発明の一実施例に基づいて構成した表面電位検出装
置における各検知電極由来の出力と、被測定表面−表面
電位検出装置間の距離の関係を示す図である。第７図
は、従来の表面電位検出装置の一例を示す断面図であ
る。第８図は、従来の表面電位検出装置における補正手
段の一例を示す概略ブロック図である。第９図は、従来
の表面電位検出装置の他の例を示す断面図である。第１
０図は、第９図に示した表面電位検出装置における被測
定表面と検知電極との間に形成される電気力線の形状を
説明するための断面図である。第１１図は、従来の表面
電位検出装置のさらに他の例における補正手段を示す断
面図である。第１２図は、第１１図に示した従来例にお
ける各検知電極の出力と、表面電位検出装置−被測定表
面間の設定距離との関係を示す図である。第１３図は、
第１１図に示した従来例において、検知電極をケース窓
部に対して等しい位置に配置した場合の各検知電極の出
力と、被測定表面−表面電位検出装置間の設定距離との
関係を示す図である。 図において、２１はケース、２３は第１の検知電極、２
４は第２の検知電極、３１は第１の窓部、３２は第２の
窓部を示す。FIG. 1 is a sectional view showing a surface potential detecting device according to an embodiment of the present invention. FIG. 2 is an enlarged cross-sectional view showing a main part of the surface potential detecting device of FIG. FIG. 3 is a plan view showing the arrangement of the detection electrodes used in the embodiment shown in FIG. FIG. 4 is a plan view showing an insulating substrate used in the embodiment shown in FIG. 1 and an electronic component mounted on the substrate. FIG. 5 is a schematic block diagram of a circuit portion of the embodiment shown in FIG. Figure 6 shows
It is a figure which shows the relationship between the output from each detection electrode in the surface potential detection apparatus comprised based on one Example of this invention, and the distance between the to-be-measured surface-surface potential detection apparatus. FIG. 7 is a sectional view showing an example of a conventional surface potential detecting device. FIG. 8 is a schematic block diagram showing an example of the correction means in the conventional surface potential detecting device. FIG. 9 is a cross-sectional view showing another example of the conventional surface potential detecting device. First
FIG. 0 is a cross-sectional view for explaining the shape of the lines of electric force formed between the surface to be measured and the detection electrode in the surface potential detecting device shown in FIG. FIG. 11 is a sectional view showing a correction means in still another example of the conventional surface potential detecting device. FIG. 12 is a diagram showing the relationship between the output of each sensing electrode and the set distance between the surface potential detecting device and the surface to be measured in the conventional example shown in FIG. Figure 13 shows
In the conventional example shown in FIG. 11, the relationship between the output of each detection electrode and the set distance between the surface to be measured and the surface potential detection device when the detection electrode is arranged at the same position with respect to the case window portion is shown. It is a figure. In the figure, 21 is a case, 23 is the first detection electrode, 2
Reference numeral 4 is a second detection electrode, 31 is a first window portion, and 32 is a second window portion.
Claims (1)
装置であって、 被測定表面から所定距離を隔てて配置され、被測定表面
の電位に応じて電荷が表面に誘起されるように構成され
た第１および第２の検知電極と、 前記第１および第２の検知電極を収納してなり、かつ前
記各検知電極に被測定表面よりの電気力線を入射させる
ための第１および第２の窓部が形成された導電性ケース
とを備え、 第１および第２の窓部は、被測定表面との間の距離が異
なるようにずらされて形成されており、 第１および第２の検知電極上に誘起された電荷を電圧信
号として取出す第１および第２の検出手段と、 前記第１および第２の検出手段の出力の比をとり、該比
に基づいて第１または第２の検出手段の出力を補正する
補正手段とをさらに備える、表面電位検出装置。1. A device for detecting the surface potential of an object in a non-contact manner, the device being arranged at a predetermined distance from the surface to be measured so that electric charges are induced on the surface according to the potential of the surface to be measured. A first and a second sensing electrode configured as described above, and a first for accommodating the first and the second sensing electrode, and for causing the lines of electric force from the surface to be measured to enter each of the sensing electrodes. And a conductive case having a second window portion formed therein, wherein the first and second window portions are formed so as to be different from each other in distance from the surface to be measured. The ratio between the outputs of the first and second detecting means for extracting the electric charge induced on the second detecting electrode as a voltage signal and the output of the first and second detecting means is taken, and the first or the second based on the ratio. A surface further comprising a correction means for correcting the output of the second detection means. Position detection device.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP608986A JPH0614077B2 (en) | 1986-01-14 | 1986-01-14 | Surface potential detector |
| US06/929,410 US4724393A (en) | 1985-11-12 | 1986-11-10 | Surface potential detector |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP608986A JPH0614077B2 (en) | 1986-01-14 | 1986-01-14 | Surface potential detector |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS62163979A JPS62163979A (en) | 1987-07-20 |
| JPH0614077B2 true JPH0614077B2 (en) | 1994-02-23 |
Family
ID=11628803
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP608986A Expired - Lifetime JPH0614077B2 (en) | 1985-11-12 | 1986-01-14 | Surface potential detector |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0614077B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9209446B2 (en) | 2009-05-26 | 2015-12-08 | Optodot Corporation | Lithium batteries utilizing nanoporous separator layers |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH028755A (en) * | 1988-01-27 | 1990-01-12 | Nec Corp | Potential sensor |
-
1986
- 1986-01-14 JP JP608986A patent/JPH0614077B2/en not_active Expired - Lifetime
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9209446B2 (en) | 2009-05-26 | 2015-12-08 | Optodot Corporation | Lithium batteries utilizing nanoporous separator layers |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS62163979A (en) | 1987-07-20 |
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