JPS6341493B2 - - Google Patents
Info
- Publication number
- JPS6341493B2 JPS6341493B2 JP5165882A JP5165882A JPS6341493B2 JP S6341493 B2 JPS6341493 B2 JP S6341493B2 JP 5165882 A JP5165882 A JP 5165882A JP 5165882 A JP5165882 A JP 5165882A JP S6341493 B2 JPS6341493 B2 JP S6341493B2
- Authority
- JP
- Japan
- Prior art keywords
- light
- random pattern
- main scale
- pattern
- fixed point
- 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
Links
- 238000001514 detection method Methods 0.000 claims description 29
- 230000003287 optical effect Effects 0.000 claims description 8
- 238000002834 transmittance Methods 0.000 claims description 7
- 238000005286 illumination Methods 0.000 description 7
- 230000007423 decrease Effects 0.000 description 5
- 238000010586 diagram Methods 0.000 description 5
- 230000000694 effects Effects 0.000 description 2
- 230000004907 flux Effects 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
- 238000007740 vapor deposition Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
- G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
- G01D5/32—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light
- G01D5/34—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells
- G01D5/36—Forming the light into pulses
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Length Measuring Devices By Optical Means (AREA)
- Optical Transform (AREA)
Description
【発明の詳細な説明】
本発明は光学的な定点検出装置に関し、特に光
電式エンコーダの原点位置を精度よく検出するた
めに、その原点位置にランダムな明暗の格子を設
けた原点検出装置に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical fixed point detection device, and more particularly to an origin detection device in which a random bright and dark grid is provided at the origin position of a photoelectric encoder in order to accurately detect the origin position.
従来より光電式エンコーダ、特にインクリメン
タル形のエンコーダにおいてはスケール上に一定
ピツチで設けられた明暗の格子数を、測定対象物
の移動や回転に伴つて計数している。この明暗の
格子は直接スケール上の絶対的な位置を表わすも
のではないので、何らかの方法で、スケール上の
定点、例えば原点を検出している。この原点検出
の一例としてスケール上のランダムパターンを設
けた方法が知られている。 Conventionally, photoelectric encoders, particularly incremental encoders, count the number of bright and dark grids provided at a constant pitch on a scale as the object to be measured moves or rotates. Since this bright and dark grid does not directly represent an absolute position on the scale, a fixed point on the scale, such as the origin, is detected by some method. As an example of this origin detection method, a method in which a random pattern is provided on a scale is known.
ランダムパターンとは明暗の格子を乱数的に測
長又は測角方向に配列したもので、格子の明部、
暗部の幅もランダムに形成されている。このよう
なランダムパターンを光電検出すると、第１図に
示すような光電信号が得られる。この光電信号の
波形は被測定物が等速度で移動した場合を示し、
時間t1からt2まで光電信号は零から徐々に増加す
る。そして時間t2において、先鋭なパルスとな
り、時間t2からt3までは徐々に減少する。 A random pattern is a pattern in which light and dark grids are randomly arranged in the length or angle measurement direction.
The width of the dark area is also randomly formed. When such a random pattern is photoelectrically detected, a photoelectric signal as shown in FIG. 1 is obtained. The waveform of this photoelectric signal indicates the case where the object to be measured moves at a constant speed.
From time t 1 to t 2 the photoelectric signal gradually increases from zero. Then, at time t2 , the pulse becomes sharp, and gradually decreases from time t2 to t3 .
このとき、光電信号の先鋭なパルス部分を有効
部Ａ、その他のノイズ部分を非有効部Ｂとする
と、一般に有効部Ａの波高値（電位零から）に対
して非有効部Ｂの波高値は約1/2である。そこで
この光電信号から有効部Ａのみを所定の基準レベ
ルで２値化すれば、スケール上の原点位置は正確
に検出できる。例えば光電信号を有効部Ａの半分
のレベルで２値化したとき、得られる矩形波信号
の幅はちようどスケール上の最小目盛間隔と等し
くなるように定められている。 At this time, assuming that the sharp pulse part of the photoelectric signal is an effective part A and the other noise part is an ineffective part B, the peak value of the ineffective part B is generally equal to the peak value of the effective part A (from zero potential). It is about 1/2. Therefore, if only the effective portion A is binarized from this photoelectric signal at a predetermined reference level, the origin position on the scale can be accurately detected. For example, when a photoelectric signal is binarized at half the level of the effective part A, the width of the resulting rectangular wave signal is determined to be exactly equal to the minimum graduation interval on the scale.
ところがランダムパターンが何らかの原因でよ
ごれていたり、ランダムパターンの照明光量が変
動したりすると、ノイズの影響を受けやすく、有
効部Ａと非有効部Ｂとの割合が変化してしまう。
このため、２値化された信号の矩形波の幅が広く
なつて、原点位置の検出に誤差が生じるという欠
点があつた。 However, if the random pattern becomes dirty for some reason or the amount of illumination light of the random pattern fluctuates, it will be susceptible to noise and the ratio of effective area A to ineffective area B will change.
As a result, the width of the rectangular wave of the binarized signal becomes wider, resulting in an error in detecting the origin position.
そこで本発明は、有効部Ａの非有効部Ｂに対す
る割合を増大した光電信号を発生する光学式定点
検出装置を得ることを目的とする。 SUMMARY OF THE INVENTION Therefore, an object of the present invention is to obtain an optical fixed point detection device that generates a photoelectric signal in which the ratio of the effective part A to the ineffective part B is increased.
このため本発明においては、スケール上のラン
ダムパターン以外の部分で、光電検出用の装置が
対向する部分に光電信号の有効部Ａと非有効部Ｂ
との波高値の比、例えば約1/2（50％）と等しい
透過率の光学フイルターを設けることによつて、
上記目的を達成するものである。 Therefore, in the present invention, the effective part A and the ineffective part B of the photoelectric signal are placed in the part other than the random pattern on the scale, where the photoelectric detection device faces.
By providing an optical filter with a transmittance equal to the ratio of the peak value to, for example, approximately 1/2 (50%),
This aims to achieve the above objectives.
次に本発明の実施例を図面に基づいて説明す
る。第２図は光電式エンコーダとしてロータリー
エンコーダを示す斜視図である。 Next, embodiments of the present invention will be described based on the drawings. FIG. 2 is a perspective view showing a rotary encoder as a photoelectric encoder.
測定対象物と連結された軸１０にはガラス材を
円板状に加工した主スケール１１が同軸に固着さ
れている。この主スケール１１上には、軸１０と
同心状に検出トラツクが定められ、検出トラツク
上の所定位置、例えば１ケ所にランダムパターン
１１ａが設けられる。されに検出トラツク上のラ
ンダムパターン１１ａ以外の部分には、光透過率
が約50％のフイルター部１１ｂが設けられる。一
方、主スケール１１の下方にはガラス材でできた
読取板１２が配置されており、主スケール１１の
検出トラツクと対向する位置にランダムパターン
１２ａが設けられている。また読取板１２には、
単に光を透過するだけの窓１２ｂが設けられてい
る。そして、主スケール１１の上方には光源とし
ての発光ダイオード１３（以下LED１３と呼ぶ
ことにする。）が配置されており、LED１３から
の光束は主スケール１１の検出トラツクを介し
て、読取板１２に達する。この際LED１３の一
部の光束は、主スケール１１の検出トラツク周辺
の透明部分を介して窓１２ｂに達する。 A main scale 11 made of a glass material processed into a disk shape is fixed coaxially to a shaft 10 connected to an object to be measured. A detection track is defined on the main scale 11 concentrically with the axis 10, and a random pattern 11a is provided at a predetermined position, for example, one location, on the detection track. Furthermore, a filter portion 11b having a light transmittance of about 50% is provided on the detection track other than the random pattern 11a. On the other hand, a reading plate 12 made of glass is arranged below the main scale 11, and a random pattern 12a is provided at a position facing the detection track of the main scale 11. Also, on the reading plate 12,
A window 12b is provided that simply transmits light. A light emitting diode 13 (hereinafter referred to as LED 13) is arranged above the main scale 11 as a light source, and the luminous flux from the LED 13 passes through the detection track of the main scale 11 to the reading plate 12. reach At this time, a part of the luminous flux of the LED 13 reaches the window 12b via the transparent portion of the main scale 11 around the detection track.
さて、読取板１２の下方には受光素子１４，１
５が配置されており、受光素子１４は主スケール
１１の検出トラツクとランダムパターン１２ａと
を通過した光量を光電検出し、受光素子１５は主
スケール１１の透明部分と窓１２ｂとを通過した
光量を光電検出する。差動増幅回路１６は、受光
素子１４，１５の両光電信号の差を演算して、原
点信号を出力する。尚以上の説明において読取板
１２，LED１３、受光素子１４，１５及び差動
増幅回路１６は読取手段を構成する。 Now, below the reading plate 12 are light receiving elements 14, 1.
The light receiving element 14 photoelectrically detects the amount of light that has passed through the detection track of the main scale 11 and the random pattern 12a, and the light receiving element 15 detects the amount of light that has passed through the transparent portion of the main scale 11 and the window 12b. Photoelectric detection. The differential amplifier circuit 16 calculates the difference between the photoelectric signals of the light receiving elements 14 and 15, and outputs an origin signal. In the above description, the reading plate 12, the LED 13, the light receiving elements 14 and 15, and the differential amplifier circuit 16 constitute a reading means.
また不図示ではあるが、主スケール１１には検
出トラツクと同心状に回転量や角度を計測するた
めの目盛帯が設けられている。さらに、この目盛
帯と対向して目盛を読み取る光電検出部も設けら
れている。 Although not shown, the main scale 11 is provided with a scale band concentrically with the detection track for measuring rotation amounts and angles. Further, a photoelectric detection section for reading the scale is also provided facing the scale band.
次に主スケール１１のフイルター部１１ｂにつ
いて第３図に基づいて説明する。本実施例ではフ
イルター部１１ｂの透過率を約50％にするため
に、検出トラツク上に環状の透過部R1と遮光部
R2とを交互に同心円状に配列したスリツトパタ
ーンを設ける。このスリツトパターンは透過部
R1と遮光部R2との各幅を同一にして、検出トラ
ツクの幅方向に関しては、光の透過率を50％とし
たものである。 Next, the filter section 11b of the main scale 11 will be explained based on FIG. 3. In this embodiment, in order to make the transmittance of the filter part 11b approximately 50%, an annular transmitting part R1 and a light shielding part are provided on the detection track.
A slit pattern in which R 2 and R 2 are arranged concentrically alternately is provided. This slit pattern
The widths of R1 and the light shielding part R2 are made the same, and the light transmittance in the width direction of the detection track is set to 50%.
また、第４図は差動増幅回路１６の具体的な回
路接続図である。受光素子１４，１５は共にフオ
トダイオードであり、並列に逆接続されて演算増
幅器２０の反転入力と非反転入力との間に接続さ
れる。演算増幅器２０の出力と反転入力との間に
は帰環抵抗Rfが接続される。尚、非反転入力に
は、オフセツトレベルの調整や出力信号のレベル
シフトのために、電圧Vsが印加される。 Further, FIG. 4 is a specific circuit connection diagram of the differential amplifier circuit 16. The light receiving elements 14 and 15 are both photodiodes, and are connected in parallel and inversely between the inverting input and the non-inverting input of the operational amplifier 20. A feedback resistor Rf is connected between the output and the inverting input of the operational amplifier 20. Note that a voltage Vs is applied to the non-inverting input in order to adjust the offset level and shift the level of the output signal.
以上の如き構成において、その動作を第５図を
参照して説明する。第５図は差動増幅回路１６の
出力信号の波形図である。尚第５図において時間
ｔは横軸に定め、主スケール１１は等速度で回転
しているものとする。 The operation of the above configuration will be explained with reference to FIG. FIG. 5 is a waveform diagram of the output signal of the differential amplifier circuit 16. In FIG. 5, time t is set on the horizontal axis, and it is assumed that the main scale 11 is rotating at a constant speed.
主スケール１１の回転に伴つて、時間t1までは
読取板１２のランダムパターン１２ａとフイルタ
ー部１１ｂとが対向しているため、出力信号はほ
ぼ一定値となる。これは１つのランダムパターン
全面については透過率が約50％のフイルターとし
て機能するからである。すなわち、ランダムパタ
ーン１２ａの明暗の格子縞に対してフイルター部
１１ｂの格子縞はほぼ直交するように形成されて
いるから、LED１３からの照明光量はフイルタ
ー部１１ｂで50％減少し、さらにランダムパター
ン１２ａで約50％減少する。従つて、LED１３
の照明光量のうち約25％が受光素子１４に達す
る。さらに主スケール１１が回転した時間t1から
ランダムパターン１１ａとランダムパターン１２
ａとが重り始めると、出力信号はわずかに減少す
る。このように出力信号が定常的な一定値から減
少するのは、フイルター１１ｂとランダムパター
ン１１ａとの両者がランダムパターン１２ａと重
るからである。 As the main scale 11 rotates, the random pattern 12a of the reading plate 12 and the filter section 11b are opposed to each other until time t1 , so that the output signal has a substantially constant value. This is because the entire surface of one random pattern functions as a filter with a transmittance of about 50%. That is, since the lattice fringes of the filter section 11b are formed to be almost perpendicular to the bright and dark lattice fringes of the random pattern 12a, the amount of illumination light from the LED 13 is reduced by 50% in the filter section 11b, and furthermore, the amount of illumination light from the random pattern 12a is reduced by about 50%. Reduced by 50%. Therefore, LED13
Approximately 25% of the amount of illumination light reaches the light receiving element 14. Furthermore, from time t 1 when the main scale 11 rotates, the random pattern 11a and the random pattern 12
When a starts to overlap, the output signal decreases slightly. The reason why the output signal decreases from a steady constant value in this way is because both the filter 11b and the random pattern 11a overlap with the random pattern 12a.
その後時間t2においてランダムパターン１１ａ
とランダムパターン１２ａとの明暗の格子縞が完
全に一致して、出力信号は鋭いピークとなる。こ
のとき、LED１３の照明光量のうち約50％が受
光素子１４に達する。さらに時間t2からt3にかけ
て出力信号は一度わずかに減少した後、時間t3以
降は再び一定値になる。ここで、出力信号の定常
的な一定値からのピーク部分を有効部A′とし、
その一定値からわずかに減少した部分を非有効部
B′とする。このように主スケール１１の検出ト
ラツク上のランダムパターン１１ａ以外の部分に
50％のフイルター部１１ｂを設けることによつ
て、有効部A′と非有効部B′との比はおよそ４：
１になる。 Then at time t 2 the random pattern 11a
The bright and dark lattice fringes of the random pattern 12a and the random pattern 12a completely match, and the output signal has a sharp peak. At this time, approximately 50% of the amount of illumination light from the LED 13 reaches the light receiving element 14. Further, the output signal decreases slightly from time t 2 to t 3 and then becomes constant again from time t 3 onwards. Here, the peak part of the output signal from a steady constant value is defined as the effective part A',
The part that slightly decreases from that constant value is the ineffective part.
Let it be B′. In this way, the random pattern 11a on the detection track of the main scale 11 is
By providing the 50% filter portion 11b, the ratio of the effective area A' to the ineffective area B' is approximately 4:
Becomes 1.
尚、この際受光素子１５はLED１３の照明光
量の変動によつて、受光素子１４の光電信号が変
動するのを相殺して、差動増幅回路１６の出力信
号が安定になるように動く。以上の如く本実施例
によれば、原点検出に必要な有効部A′を非有効
部B′よりもかなり大きくできる。このためノイ
ズの影響を受けにくく、極めて安定な原点検出が
行なわれる。また、フイルター部１１ｂはランダ
ムパターン１１ａと同一の検出トラツク上に設け
るのみであるから、特別に他のトラツクや、受光
素子等を必要とせず、きわめて簡単な構成で有効
部A′と非有効分B′との比を大きくすることがで
きる。 At this time, the light-receiving element 15 moves so as to offset fluctuations in the photoelectric signal of the light-receiving element 14 due to fluctuations in the amount of illumination light from the LED 13, thereby stabilizing the output signal of the differential amplifier circuit 16. As described above, according to this embodiment, the effective portion A' required for origin detection can be made considerably larger than the ineffective portion B'. Therefore, the origin is hardly affected by noise and extremely stable origin detection is performed. In addition, since the filter section 11b is only provided on the same detection track as the random pattern 11a, there is no special need for other tracks or light-receiving elements, and the effective section A' and the ineffective section can be detected with a very simple configuration. The ratio with B' can be increased.
以上、本発明の実施例において受光素子１５は
単に照明光のレフアレンス検出として働くもので
ある。そこで窓１２ｂと受光素子１５との間に進
退自在な調整ネジを設けることによつて、有効部
A′と非有効部B′との比を変えず、差動増幅回路
１６の出力信号をレベルシフトさせることができ
る。 As described above, in the embodiment of the present invention, the light-receiving element 15 simply functions as a reference detector for illumination light. Therefore, by providing an adjustment screw that can move forward and backward between the window 12b and the light receiving element 15, the effective part
The level of the output signal of the differential amplifier circuit 16 can be shifted without changing the ratio between A' and the ineffective part B'.
また、主スケール１１のフイルター部１１ｂと
して、ニユートラル・デンシテイ（ND）フイル
ターや色フイルター等を蒸着によつて設けても同
様の効果が得られる。さらに本発明はロータリー
エンコーダだけではなく、リニアエンコーダにも
何ら変更を処さずに使えるばかりか、その他、一
般の光学式の定位置検出にも使用し得るものであ
る。 Furthermore, the same effect can be obtained by providing a neutral density (ND) filter, a color filter, or the like as the filter portion 11b of the main scale 11 by vapor deposition. Furthermore, the present invention can be used not only for rotary encoders but also for linear encoders without any modification, and can also be used for general optical fixed position detection.
以上説明したように本発明によれば、主スケー
ルのランダムパターン以外の部分に、光透過率が
有効部と非有効部との比に略等しいフイルターを
設けたので、極めて簡単な構成で定点検出用の信
号の有効部が大きくなり、ノイズの影響を受けに
くくなるという効果が生じる。 As explained above, according to the present invention, a filter is provided in the part other than the random pattern of the main scale, and the light transmittance is approximately equal to the ratio of the effective part to the ineffective part, so fixed point detection is possible with an extremely simple configuration. The effect is that the effective part of the signal becomes larger, making it less susceptible to noise.
第１図は従来の原点信号の波形図、第２図は本
発明の実施例を示すロータリーエンコーダの斜視
図、第３図は主スケール１１上のランダムパター
ン１１ａとフイルター部１１ｂの一部拡大図、第
４図は差動増幅回路１６の具体的な接続図、第５
図は差動増幅回路１６の出力信号の波形図であ
る。
主要部分の符号の説明、１１……主スケール、
１１ａ，１２ａ……ランダムパターン、１１ｂ…
…フイルター部。
FIG. 1 is a waveform diagram of a conventional origin signal, FIG. 2 is a perspective view of a rotary encoder showing an embodiment of the present invention, and FIG. 3 is a partially enlarged view of the random pattern 11a on the main scale 11 and the filter section 11b. , FIG. 4 is a specific connection diagram of the differential amplifier circuit 16, and FIG.
The figure is a waveform diagram of the output signal of the differential amplifier circuit 16. Explanation of the symbols of the main parts, 11...Main scale,
11a, 12a...Random pattern, 11b...
...filter section.
Claims (1)
ダムパターンを所定の位置に設けた主スケール
と；該主スケールと対向して相対移動可能に設け
られると共に、前記ランダムパターンを光電的に
読み取つて検出信号を発生する読取手段とを備え
た定点検出装置において、前記主スケール上のラ
ンダムパターン以外の前記読取手段と対向可能な
部分に、前記検出信号の有効部と非有効部との比
に応じた透過率の光学フイルターを設けたことを
特徴とする光学式定点検出装置。 ２ 特許請求の範囲第１項記載の装置において、
前記光学フイルターは前記主スケールと読取手段
の相対移動方向とほぼ直交する方向に、光透過部
と遮光部とを一定の間隔で交互に配列した明暗ス
リツトパターンであることを特徴とする光学定点
検出装置。[Claims] 1. A main scale provided at a predetermined position with a random pattern in which stripes of light-transmitting parts and light-blocking parts are arranged in random numbers; In a fixed point detection device equipped with a reading means that photoelectrically reads a pattern and generates a detection signal, an effective part of the detection signal and a non-effective part of the detection signal are placed on a part of the main scale other than the random pattern that can face the reading means. An optical fixed point detection device characterized by being provided with an optical filter having a transmittance depending on the ratio to the effective part. 2. In the device according to claim 1,
An optical fixed point characterized in that the optical filter has a light and dark slit pattern in which light transmitting parts and light shielding parts are arranged alternately at a constant interval in a direction substantially perpendicular to the direction of relative movement between the main scale and the reading means. Detection device.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5165882A JPS58168914A (en) | 1982-03-30 | 1982-03-30 | Optical detector for fix point |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5165882A JPS58168914A (en) | 1982-03-30 | 1982-03-30 | Optical detector for fix point |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS58168914A JPS58168914A (en) | 1983-10-05 |
| JPS6341493B2 true JPS6341493B2 (en) | 1988-08-17 |
Family
ID=12892970
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP5165882A Granted JPS58168914A (en) | 1982-03-30 | 1982-03-30 | Optical detector for fix point |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS58168914A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0365687U (en) * | 1989-10-27 | 1991-06-26 | ||
| JPH049290U (en) * | 1990-05-11 | 1992-01-27 | ||
| EP2650654A1 (en) | 2012-04-11 | 2013-10-16 | Mitutoyo Corporation | Encoder |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS60183818U (en) * | 1984-05-16 | 1985-12-06 | 東洋電装株式会社 | rotary encoder |
| US5168364A (en) * | 1988-11-30 | 1992-12-01 | Canon Kabushiki Kaisha | Image sensing apparatus |
-
1982
- 1982-03-30 JP JP5165882A patent/JPS58168914A/en active Granted
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0365687U (en) * | 1989-10-27 | 1991-06-26 | ||
| JPH049290U (en) * | 1990-05-11 | 1992-01-27 | ||
| EP2650654A1 (en) | 2012-04-11 | 2013-10-16 | Mitutoyo Corporation | Encoder |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS58168914A (en) | 1983-10-05 |
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