JPH0481612A - Scale plate of optical encoder and optical encoder using the scale plate - Google Patents
Scale plate of optical encoder and optical encoder using the scale plateInfo
- Publication number
- JPH0481612A JPH0481612A JP19479090A JP19479090A JPH0481612A JP H0481612 A JPH0481612 A JP H0481612A JP 19479090 A JP19479090 A JP 19479090A JP 19479090 A JP19479090 A JP 19479090A JP H0481612 A JPH0481612 A JP H0481612A
- Authority
- JP
- Japan
- Prior art keywords
- light
- scale plate
- diffraction grating
- plate
- scale
- 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.)
- Granted
Links
- 230000003287 optical effect Effects 0.000 title claims abstract description 20
- 230000005540 biological transmission Effects 0.000 claims description 20
- 230000002452 interceptive effect Effects 0.000 claims description 3
- 239000011521 glass Substances 0.000 description 4
- 238000010586 diagram Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 239000011347 resin Substances 0.000 description 2
- 229920005989 resin Polymers 0.000 description 2
- 238000009751 slip forming Methods 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 239000005357 flat glass Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
Landscapes
- Optical Transform (AREA)
Abstract
Description
【発明の詳細な説明】
（産業上の利用分野）
本発明は光学式エンコーダの目盛板およびこの目盛板を
用いた光学式エンコーダに関する。DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a scale plate for an optical encoder and an optical encoder using this scale plate.
（従来の技術）
レーザ光源を用いたエンコーダは、第３図に示すように
、透明板の表面に一定ピッチの凹凸が連続して形成され
た目盛板ａを用い、これをレーザｂの前方を横切ってス
ライドすることかできるように配置し、この目盛板ａを
透過することによって形成された１次回折光Ｃ＋ Ｃ
２をミラーｄ、 ｄ２とハーフミラ−ｅとによって
干渉させ、この干渉光ｆを受光素子ｇで受光し、その出
力パルスをカウンタｈでカウントするように構成されて
いる。(Prior art) As shown in Fig. 3, an encoder using a laser light source uses a scale plate a on which irregularities at a constant pitch are continuously formed on the surface of a transparent plate. The first-order diffracted light C+ C formed by passing through this scale plate a arranged so that it can be slid across
2 is caused to interfere with each other by mirrors d and d2 and a half mirror e, this interference light f is received by a light receiving element g, and its output pulses are counted by a counter h.
この構成によれば、目盛板ａの目盛数の２倍のパルスが
得られ、目盛板ａに連結した被測定物（図示しない）の
移動量を精度よく測定することができる。According to this configuration, it is possible to obtain twice as many pulses as the number of graduations on the scale plate a, and it is possible to accurately measure the amount of movement of the object to be measured (not shown) connected to the scale plate a.
（発明が解決しようとする課題）
上述した従来のエンコーダにおいて、分解能を更に上げ
てゆくには、３次回折光、５次回折光等高次回折光を使
用することが考えられる。(Problems to be Solved by the Invention) In order to further increase the resolution in the conventional encoder described above, it is conceivable to use higher-order diffracted light such as third-order diffracted light and fifth-order diffracted light.
しかしながら、高次回折光は１次回折光に比べて光量が
小さいため、ノイズを拾い易く、高精度の測定を行なう
ことができない。However, since the amount of high-order diffracted light is smaller than that of first-order diffracted light, it is easy to pick up noise, making it impossible to perform highly accurate measurements.
本発明は、従来のこのような課題を解決することをその
目的とするものである。The present invention aims to solve these conventional problems.
（課題を解決するだめの手段）
上記の目的を達成するために、本発明の光学式エンコー
ダの目盛板及び、この目盛板を用いた光学式エンコーダ
は、次のように構成されている。(Means for Solving the Problems) In order to achieve the above object, a scale plate of an optical encoder of the present invention and an optical encoder using this scale plate are constructed as follows.
請求項１記載の目盛板は、板状透明板の表裏両側に透過
型回折格子が形成されたことを特徴とする請求項２記載
の目盛板は、板状透明板の表側に透過型回折格子が形成
され、裏側に反射型回折格子が形成されたことを特徴と
する請求項３の光学式エンコーダは、レーザ光源と、該
レーザ光源の前方を横切ってスライドする目盛板と、こ
の目盛板によって形成された回折光を干渉させる光学的
手段と、前記干渉光を受光する受光素子と、受光素子の
出力パルスをカウントするカウンタとを備えた光学式エ
ンコーダにおいて、前記目盛板は板状透明板の表裏両側
に透過型回折格子が形成されたものであることを特徴と
する請求項４の光学式エンコーダは、前記光学式エンコ
ーダにおいて、前記目盛板は板状透明板の表側に透過型
回折格子が形成され、裏側に反射型回折格子が形成され
たものであることを特徴とする。The scale plate according to claim 1 is characterized in that a transmission type diffraction grating is formed on both the front and back sides of the plate-like transparent plate.The scale plate according to claim 2 is characterized in that a transmission type diffraction grating is formed on the front side of the plate-like transparent plate. An optical encoder according to claim 3, characterized in that a reflection type diffraction grating is formed on the back side of the optical encoder, a laser light source, a scale plate that slides across the front of the laser light source, and a scale plate that In an optical encoder comprising an optical means for interfering the formed diffracted light, a light receiving element for receiving the interference light, and a counter for counting output pulses of the light receiving element, the scale plate is made of a plate-like transparent plate. In the optical encoder according to claim 4, the scale plate has a transmission type diffraction grating formed on the front side of a plate-like transparent plate. A reflection type diffraction grating is formed on the back side.
（作 用）
請求項１記載の目盛板によれば、目盛板の表の透過型回
折格子で形成された±１次回折光を更に裏の透過型回折
格子で回折させ、±１次回折光の±１次回折光を得る。(Function) According to the scale plate according to claim 1, the ±1st order diffraction light formed by the transmission type diffraction grating on the front side of the scale plate is further diffracted by the transmission type diffraction grating on the back side, so that the ±1st order diffraction light beams are further diffracted by the transmission type diffraction grating on the back side. Obtain first-order diffracted light.
請求項２記載の目盛板によれば、目盛板の表の透過型回
折格子で形成された±１次回折光を裏の反射型回折格子
で反射させて±１次回折光の±１次回折光を得る。そし
て更にこの回折光を表の透過型回折格子で回折させてこ
の回折光の１次回折光を得る。According to the scale plate according to the second aspect, the ±1st-order diffraction light formed by the transmission type diffraction grating on the front side of the scale plate is reflected by the reflection type diffraction grating on the back side to obtain the ±1st-order diffraction light of the ±1st-order diffraction light. . Then, this diffracted light is further diffracted by a front transmission type diffraction grating to obtain a first-order diffracted light of this diffracted light.
請求項１及び２記載の目盛板から得られた１次回折光に
よれば、前述の高次回折光を利用したのと同じく、分解
能を上げることかでき、その光量も比較的大きいので、
高精度の測定を行なうことができる。According to the first-order diffracted light obtained from the scale plate according to claims 1 and 2, the resolution can be increased in the same way as using the above-mentioned higher-order diffracted light, and the amount of light is also relatively large.
Highly accurate measurements can be made.
（実施例） 以下本発明の実施例を図面につき説明する。(Example) Embodiments of the present invention will be described below with reference to the drawings.
第１図は第１実施例のエンコーダの全体構成を示す。FIG. 1 shows the overall configuration of an encoder according to a first embodiment.
同図において、１はレーザ光源としてのレーザダイオー
ドで、その前方を横切ってＸ方向にスライド自在に目盛
板２が配設されている。In the figure, reference numeral 1 denotes a laser diode as a laser light source, and a scale plate 2 is disposed across the front of the diode so as to be slidable in the X direction.
目盛板２は、板状ガラス層３の表裏両側に透明な透過型
回折格子４．５が積層され一体化された構造になってお
り、この透過型回折格子４．５は各々一定ピツチの凹凸
が連続して形成された構造を有する。The scale plate 2 has an integrated structure in which transparent transmission type diffraction gratings 4.5 are laminated on both the front and back sides of the plate glass layer 3, and each of the transmission type diffraction gratings 4.5 has irregularities of a constant pitch. The structure has a continuous structure.
この目盛板２のレーザダイオード１とは反対側には、目
盛板２から出射した±１次回折光７、及び−１次回折光
７２を各々反射する一対のミラー８１８２とこの一対の
ミラー８１８２で各反射した±１次回折光７１と一１次
回折光７２を干渉させるハーフミラ−９と、このハーフ
ミラ−９で形成した干渉光１０を受光する受光素子１１
が配設され、この受光素子１１にはカウンタ１２が接続
されている。On the opposite side of the scale plate 2 from the laser diode 1, there is a pair of mirrors 8182 that respectively reflect the ±1st-order diffracted light 7 and -1st-order diffracted light 72 emitted from the scale plate 2; a half mirror 9 that makes the ±1st-order diffracted light 71 and the 1st-order diffracted light 72 interfere with each other; and a light-receiving element 11 that receives the interference light 10 formed by the half mirror 9.
A counter 12 is connected to the light receiving element 11 .
レーザダイオード１からのレーザ光がＸ方向に移動して
いる目盛板２に入射すると、入射点は移動に応じて回折
格子４の凸部１３ａと凹部１３ｂの交互になるから、目
盛板２内の光路長の違いにより、凸部１３ａと凹部１３
ｂの時では出射光に位相差が生じる。また、レーザ光は
、レーザ光の目盛板２への入射時に回折格子４で回折さ
れ、目盛板２からの出射時にも回折格子５で回折される
。When the laser beam from the laser diode 1 enters the scale plate 2 moving in the Due to the difference in optical path length, the convex portion 13a and the concave portion 13
At time b, a phase difference occurs in the emitted light. Further, the laser beam is diffracted by the diffraction grating 4 when the laser beam is incident on the scale plate 2, and is also diffracted by the diffraction grating 5 when the laser beam is emitted from the scale plate 2.
この回折格子４による＋１次回折光６１及びν
１次回折光６□及び−１次回折光６２が各々裏面の回折
格子５で再び回折されたときの＋１次回折光及び−１次
回折光すなわち＋１次回折光表わされる。この２つの回
折光７□及び７２をミラー８□及び８２で各々反射させ
、ハーフミラ−９で干渉させると、この干渉光１０は、
目盛板２のスライドに従ってその振幅が
２ ｉ＋ｃｏｓ（８ｇｘ／ｐ）ｌ −（１）但し
、ｐ：凹凸のピッチ
Ｘ：目盛板２のＸ方向への移動量。The +1st-order diffracted light 61 and the -1st-order diffracted light 61 and -1st-order diffracted light 62 by this diffraction grating 4 are respectively represented by the +1st-order diffracted light and -1st-order diffracted light, that is, the +1st-order diffracted light when they are each diffracted again by the diffraction grating 5 on the back side. . When these two diffracted lights 7□ and 72 are reflected by mirrors 8□ and 82 and interfered by half mirror 9, this interference light 10 becomes
As the scale plate 2 slides, its amplitude changes 2 i + cos (8gx/p)l - (1), where p: pitch of unevenness X: amount of movement of the scale plate 2 in the X direction.
の式で示すように変化する。すなわち、目盛かＸ方向に
１ピツチｐ移動すると、光の明暗が４回生じることにな
る。この干渉光１０を受光素子１１で感知し、その出力
パルスをカウンタ１２でカウントする。このカウント数
から目盛板２の移動量を測定する。It changes as shown in the equation. That is, when the scale moves one pitch p in the X direction, the light will change in brightness and darkness four times. This interference light 10 is sensed by a light receiving element 11, and its output pulses are counted by a counter 12. The amount of movement of the scale plate 2 is measured from this count number.
前記目盛板２は、三層構造になっているか、単一材料（
樹脂やガラス）より成る一体物であってもよい。The scale plate 2 has a three-layer structure or is made of a single material (
It may also be an integral body made of resin or glass.
第２図は、第２実施例のエンコーダの全体構成を示す。FIG. 2 shows the overall configuration of an encoder according to a second embodiment.
同図において、２人はレーザダイオード１の前方を横切
ってスライド自在の目盛板である。この目盛板２Ａは、
ガラス層１４の表側に透過型回折格子１５か、裏側に反
射型回折格子１６かそれぞれ積層され一体化されている
。この反射型回折格子１６は、表側に一定ピッチの凹凸
が連続して形成されたガラス板（又は樹脂板） １７の
上にアルミニウム蒸着層等の反射面１８が形成されたも
のであり、これと透過型回折格子１５とをガラス層１４
に一体化する。In the figure, two scale plates are slidable across the front of the laser diode 1. This scale plate 2A is
A transmission type diffraction grating 15 and a reflection type diffraction grating 16 are laminated and integrated on the front side and the back side of the glass layer 14, respectively. This reflective diffraction grating 16 has a reflective surface 18 such as an aluminum vapor deposited layer formed on a glass plate (or resin plate) 17 on which unevenness at a constant pitch is continuously formed on the front side. The transmission type diffraction grating 15 and the glass layer 14
to be integrated into.
この実施例では、目盛板２人の裏側に反射型回折格子１
６が形成されているので、目盛板２人に入射したレーザ
光１９は、回折光となって目盛板２人の同じ側から出射
する。したがって、目盛板２人から出射する＋１次回折
光２１＋及び−１次回折光２１２を各々反射するミラー
８１及び８２とこのミラー８１及び８２で反射した±１
次回折光２１、及び２１２を干渉させるハーフミラ−９
と受光素子１０はレーザダイオード１と同じ側に配置さ
れている。In this embodiment, a reflection type diffraction grating is placed on the back side of the two scale plates.
6, the laser beam 19 incident on the two scale plates becomes diffracted light and exits from the same side of the two scale plates. Therefore, the mirrors 81 and 82 that respectively reflect the +1st order diffracted light 21+ and the -1st order diffracted light 212 emitted from the two scale plates, and the ±1
Half mirror 9 that interferes with the next diffracted lights 21 and 212
The light receiving element 10 and the laser diode 1 are arranged on the same side.
反射型回折格子１６での＋１次回折光の＋１次回折光２
０１は
二の＋１次回折光の＋１次回折光２０１は目盛板２Ａか
ら出射する際に、透過型回折格子Ｉ５により回折され、
その＋１次回折光２１．は
前記−１次回折光の一１次回折光２０□は、同様に目盛
板２Ａから出射する際に、透過型回折格子１５により回
折され、その−１次回折光２１２は式（２）（３）で各
々表わされる２つの回折光２１１及び２１２をハーフミ
ラ−９で干渉させると、その干渉光は、目盛板２Ａのス
ライドに沿ってその振幅か、
１次回折光の一１次回折光２０２は
の式に示すように変化する。すなわち、目盛板２Ａの目
盛がＸ方向に１ピツチｐ移動すると、その明暗か６回生
じることになる。この干渉光２２を受光素子１０で感知
し、その出力パルスをカウンタ１１でカウントする。こ
のカウント数から目盛板２Ａの移動量を測定する。+1st-order diffracted light 2 of +1st-order diffracted light at the reflection type diffraction grating 16
01 is the +1st order diffracted light 201 of the second +1st order diffracted light, which is diffracted by the transmission type diffraction grating I5 when exiting from the scale plate 2A,
The +1st order diffracted light 21. The 1st-order diffracted light 20□ of the -1st-order diffracted light is similarly diffracted by the transmission type diffraction grating 15 when emitted from the scale plate 2A, and the -1st-order diffracted light 212 is expressed by equations (2) and (3). When the two diffracted lights 211 and 212 respectively represented are made to interfere with each other by the half mirror 9, the interference light will change its amplitude along the slide of the scale plate 2A, and the 1st-order diffracted light 202 of the 1st-order diffracted light will be expressed by the following equation. It changes like this. That is, when the scale of the scale plate 2A moves one pitch p in the X direction, the brightness and darkness will occur six times. This interference light 22 is sensed by a light receiving element 10, and its output pulses are counted by a counter 11. The amount of movement of the scale plate 2A is measured from this count number.
（発明の効果）
本発明は上述のように構成されているので、従来のもの
と比べて被測定物の移動量の測定を高精度に行なうこと
ができるという効果を有する。(Effects of the Invention) Since the present invention is configured as described above, it has the effect that the amount of movement of the object to be measured can be measured with high accuracy compared to the conventional method.
第１図及び第２図は、いずれも本発明の実施例のエンコ
ーダの全体構成を示す線図、第３図は従来のエンコーダ
の全体構成を示す線図である。
１・・・レーザダイオード
２．２Ａ・・・目盛板
４．５・・・透過型回折格子
１１・・受光素子
第１図
１２・・・カウンタ
１５・・・透過型回折格子
１６・・・反射型回折格子
外３名
第２図1 and 2 are diagrams showing the overall configuration of an encoder according to an embodiment of the present invention, and FIG. 3 is a diagram showing the overall configuration of a conventional encoder. 1... Laser diode 2.2A... Scale plate 4.5... Transmission type diffraction grating 11... Light receiving element Fig. 1 12... Counter 15... Transmission type diffraction grating 16... Reflection Three people outside the type diffraction grating Figure 2
Claims (1)
たことを特徴とする光学式エンコーダの目盛板。 ２、板状透明板の表側に透過型回折格子が形成され、裏
側に反射型回折格子が形成されたことを特徴とする光学
式エンコーダの目盛板。 ３、レーザ光源と、該レーザ光源の前方を横切ってスラ
イドする目盛板と、この目盛板によって形成された回折
光を干渉させる光学的手段と、前記干渉光を受光する受
光素子と、受光素子の出力パルスをカウントするカウン
タとを備えた光学式エンコーダにおいて、前記目盛板は
板状透明板の表裏両側に透過型回折格子が形成されたも
のであることを特徴とする光学式エンコーダ。 ４、レーザ光源と、該レーザ光源の前方を横切ってスラ
イドする目盛板と、この目盛板によって形成された回折
光を干渉させる光学的手段と、前記干渉光を受光する受
光素子と、受光素子の出力パルスをカウントするカウン
タとを備えた光学式エンコーダにおいて、前記目盛板は
板状透明板の表側に透過型回折格子が形成され、裏側に
反射型回折格子が形成されたものであることを特徴とす
る光学式エンコーダ。[Scope of Claims] 1. A scale plate for an optical encoder, characterized in that a transmission type diffraction grating is formed on both the front and back sides of a plate-like transparent plate. 2. A scale plate for an optical encoder, characterized in that a transmission type diffraction grating is formed on the front side of a plate-like transparent plate, and a reflection type diffraction grating is formed on the back side. 3. A laser light source, a scale plate that slides across the front of the laser light source, an optical means for interfering with the diffracted light formed by the scale plate, a light-receiving element that receives the interference light, and a light-receiving element. 1. An optical encoder comprising a counter for counting output pulses, wherein the scale plate is a plate-shaped transparent plate with transmission type diffraction gratings formed on both sides thereof. 4. A laser light source, a scale plate that slides across the front of the laser light source, an optical means for interfering with the diffracted light formed by the scale plate, a light-receiving element that receives the interference light, and a light-receiving element. An optical encoder equipped with a counter for counting output pulses, wherein the scale plate is a plate-like transparent plate, with a transmission type diffraction grating formed on the front side and a reflection type diffraction grating formed on the back side. Optical encoder.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2194790A JP3015962B2 (en) | 1990-07-25 | 1990-07-25 | Scale plate of optical encoder and optical encoder using this scale plate |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2194790A JP3015962B2 (en) | 1990-07-25 | 1990-07-25 | Scale plate of optical encoder and optical encoder using this scale plate |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0481612A true JPH0481612A (en) | 1992-03-16 |
| JP3015962B2 JP3015962B2 (en) | 2000-03-06 |
Family
ID=16330307
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2194790A Expired - Fee Related JP3015962B2 (en) | 1990-07-25 | 1990-07-25 | Scale plate of optical encoder and optical encoder using this scale plate |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3015962B2 (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5661295A (en) * | 1994-07-28 | 1997-08-26 | Matsushita Electric Industrial Co., Ltd. | Optical encoder with dual diffraction gratings |
| WO2002023130A1 (en) * | 2000-09-13 | 2002-03-21 | Mitsubishi Denki Kabushiki Kaisha | Optical encoder |
| JP2005315649A (en) * | 2004-04-27 | 2005-11-10 | Sumitomo Heavy Ind Ltd | Detection device and stage device |
| WO2005106385A1 (en) * | 2004-04-27 | 2005-11-10 | Sumitomo Heavy Industries, Ltd. | Detector and stage device |
| JP2006010645A (en) * | 2004-06-29 | 2006-01-12 | Tohoku Univ | Detector and stage device |
-
1990
- 1990-07-25 JP JP2194790A patent/JP3015962B2/en not_active Expired - Fee Related
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5661295A (en) * | 1994-07-28 | 1997-08-26 | Matsushita Electric Industrial Co., Ltd. | Optical encoder with dual diffraction gratings |
| US5696374A (en) * | 1994-07-28 | 1997-12-09 | Matsushita Electric Industrial Co., Ltd. | Optical encoder using doubled diffraction angle based on first and second diffraction gratings |
| US5696373A (en) * | 1994-07-28 | 1997-12-09 | Matsushita Electric Industrial Co., Ltd. | Optical encoder with dual diffraction grating |
| WO2002023130A1 (en) * | 2000-09-13 | 2002-03-21 | Mitsubishi Denki Kabushiki Kaisha | Optical encoder |
| JP2005315649A (en) * | 2004-04-27 | 2005-11-10 | Sumitomo Heavy Ind Ltd | Detection device and stage device |
| WO2005106385A1 (en) * | 2004-04-27 | 2005-11-10 | Sumitomo Heavy Industries, Ltd. | Detector and stage device |
| US7502127B2 (en) | 2004-04-27 | 2009-03-10 | Sumitomo Heavy Industries, Ltd. | Sensor device and stage device |
| JP2006010645A (en) * | 2004-06-29 | 2006-01-12 | Tohoku Univ | Detector and stage device |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3015962B2 (en) | 2000-03-06 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4970388A (en) | Encoder with diffraction grating and multiply diffracted light | |
| US5448358A (en) | Optical apparatus and displacement-information measuring apparatus using the same | |
| JP3210111B2 (en) | Displacement detector | |
| EP1104543B1 (en) | Device for measuring translation, rotation or velocity via light beam interference | |
| JP2862417B2 (en) | Displacement measuring device and method | |
| JP3209914B2 (en) | Optical encoder | |
| KR101184167B1 (en) | Interferometric position encoder employing spatial filtering of diffraction orders | |
| JPS60243515A (en) | Photoelectric measuring device | |
| KR20060116859A (en) | Optical encoder | |
| JPS63231217A (en) | Measuring instrument for movement quantity | |
| EP0451780B1 (en) | Encoder | |
| JPH0481612A (en) | Scale plate of optical encoder and optical encoder using the scale plate | |
| JPH07198423A (en) | Device for measuring length or angle | |
| JPS61182522A (en) | Linear scale measuring device | |
| JP2704017B2 (en) | Optical encoder | |
| JPH0349370B2 (en) | ||
| JPH1038516A (en) | Instrument for measuring vertical displacement of stage | |
| US5559602A (en) | Rotation measuring apparatus and displacement measuring apparatus | |
| JP2603338B2 (en) | Displacement measuring device | |
| JPS6347615A (en) | Optical displacement detector | |
| JPH0399222A (en) | Encoder | |
| JP2000121388A (en) | Optical encoder | |
| SU1651167A1 (en) | Photovoltage displacement converter | |
| JPH02304313A (en) | Optical displacement meter | |
| SU1035419A1 (en) | Optical electronic device for measubring linear displacements |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| LAPS | Cancellation because of no payment of annual fees |