JP3015962B2 - Scale plate of optical encoder and optical encoder using this scale plate - Google Patents
Scale plate of optical encoder and optical encoder using this scale plateInfo
- Publication number
- JP3015962B2 JP3015962B2 JP2194790A JP19479090A JP3015962B2 JP 3015962 B2 JP3015962 B2 JP 3015962B2 JP 2194790 A JP2194790 A JP 2194790A JP 19479090 A JP19479090 A JP 19479090A JP 3015962 B2 JP3015962 B2 JP 3015962B2
- Authority
- JP
- Japan
- Prior art keywords
- scale plate
- diffraction grating
- light
- diffracted light
- plate
- 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 - Fee Related
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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。The present invention relates to a scale plate of an optical encoder and an optical encoder using the 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
スライドすることが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C1、C2を
ミラーd1、d2とハーフミラー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 in which irregularities at a constant pitch are continuously formed on the surface of a transparent plate, and the scale plate a is placed in front of a laser b. This scale plate a is arranged so that it can slide across it.
1-order diffracted light C 1, which is formed by passing through a, C 2 mirrors d 1, d 2 and is interfered by the half mirror e, receives this interference light f receiving element g, and the output pulse counter h It is configured to count by.
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, a pulse twice as many as the number of scales on the scale plate a is obtained, and the DUT (not shown) connected to the scale plate a is obtained.
Can be accurately measured.
（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。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。(Problems to be Solved by the Invention) In the conventional encoder described above, in order to further increase the resolution, it is conceivable to use higher-order diffracted light such as third-order diffracted light and fifth-order diffracted light. However, since the high-order diffracted light has a smaller light quantity than the first-order diffracted light, noise is easily picked up, and high-precision measurement cannot be performed.
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。An object of the present invention is to solve such a conventional problem.
（課題を解決するための手段） 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 the scale plate are configured as follows.
請求項１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２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 graduation plate according to claim 1 is characterized in that a transmission type diffraction grating is formed on the front side of the plate-shaped transparent plate, and a reflection type diffraction grating is formed on the back side. The optical encoder according to claim 2 is
In the optical encoder, the scale plate is formed by forming a transmission diffraction grating on a front side of a plate-shaped transparent plate and a reflection diffraction grating on a 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。(Operation) According to the scale plate of the first aspect, the ± 1st-order diffracted 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, and ± 1st-order diffraction light of ± 1st-order is formed. Second order diffracted light is obtained. The diffracted light is further diffracted by the transmission diffraction grating shown in the table to obtain a first-order diffracted light of the diffracted light.
請求項１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
上げることができ、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 the first aspect, the resolution can be increased and the amount of light is relatively large, as in the case of using the above-described high-order diffracted light. Can do it.
（実施例） 以下本発明の実施例を図面につき説明する。Embodiment An embodiment of the present invention will be described below with reference to the drawings.
第１図は参考例のエンコーダの全体構成を示す。 FIG. 1 shows the overall configuration of the encoder of the reference example.
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 FIG. 1, reference numeral 1 denotes a laser diode as a laser light source, and a scale plate 2 is provided so as to be slidable in the X direction across the front thereof.
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は各々一定ピッチの凹
凸が連続して形成された構造を有する。The scale plate 2 has a structure in which transparent transmission type diffraction gratings 4 and 5 are laminated and integrated on both front and back sides of a plate-like glass layer 3. Has a structure formed continuously.
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71及び−１次回折光
72を各々反射する一対のミラー81、82とこの一対のミラ
ー81、82で各反射した＋１次回折光71と−１次回折光72
を干渉させるハーフミラー９と、このハーフミラー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,
+ 1st-order diffracted light 71 and -1st-order diffracted light emitted from the scale plate 2
A pair of mirrors 8 which respectively reflect 7 2 1 8 2 +1 order diffracted light 71 which is each reflected by the pair of mirrors 81, 82 and -1 order diffracted light 7 2
And a light receiving element 11 for receiving the interference light 10 formed by the half mirror 9, and 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13b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 is incident on the scale plate 2 moving in the X direction, the incident points alternate between the convex portions 13a and the concave portions 13b of the diffraction grating 4 according to the movement. Due to the difference in the optical path length, there is a phase difference in the emitted light between the convex portion 13a and the concave portion 13b. The laser light is diffracted by the diffraction grating 4 when the laser light is incident on the scale 2, and is also diffracted by the diffraction grating 5 when the laser light is emitted from the scale 2.
この回折格子４による＋１次回折光61及び−１次回折
光62は、各々 及び で表わされる。この＋１次回折光61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次回折光の＋１次
回折光71は で表わされ、−１次回折光の−１次回折72は で表わされる。この２つの回折光71及び72をミラー81及
び82で各々反射させ、ハーフミラー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 但し、p:凹凸のピッチ x:目盛板２のＸ方向への移動量。Order diffracted light 6 and -1-order diffracted light 6 2 by the diffraction grating 4 are each as well as Is represented by The + 1st-order diffracted light 6 and -1-order diffracted light 6 2
Are diffracted again by the diffraction grating 5 on the back surface, the + 1st-order diffracted light and the + 1st-order diffracted light, that is, the + 1st-order diffracted light 71 In expressed, -1, -1-order diffracted 7 2-order diffracted light Is represented by It is respectively reflected the two diffracted light 7 1 and 7 2 by the mirror 8 1 and 8 2, when the interference by the half mirror 9,
The amplitude of the interference light 10 is changed according to the slide of the scale plate 2. Here, 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、目盛がＸ方向に
１ピッチ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。Changes as shown by the following equation. In other words, when the scale moves by one pitch p in the X direction, light brightness is generated four times. The interference light 10 is sensed by the light receiving element 11, and the output pulse is counted by the counter 12. The movement amount of the scale plate 2 is measured from the counted number.
前記目盛板２は、三層構造になっているが、単一材料
（樹脂やガラス）より成る一体物であってもよい。Although the scale plate 2 has a three-layer structure, it may be an integral body made of a single material (resin or glass).
第２図は、第１実施例のエンコーダの全体構成を示
す。FIG. 2 shows the overall configuration of the encoder of the first embodiment.
同図において、2A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が、裏側に反射型回
折格子16が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, reference numeral 2A denotes a scale plate which can slide across the front of the laser diode 1. In the scale plate 2A, a transmission type diffraction grating 15 is laminated on the front side of the glass layer 14, and a reflection type diffraction grating 16 is laminated on the back side thereof, and are integrated. This reflection type diffraction grating 16 has a reflection surface 18 such as an aluminum vapor-deposited layer formed on a glass plate (or a resin plate) 17 in which irregularities at a constant pitch are continuously formed on the front side. The transmission diffraction grating 15 and the glass layer 14 are integrated.
この実施例では、目盛板2Aの裏側に反射型回折格子16
が形成されているので、目盛板2Aに入射したレーザ光19
は、回折光となって目盛板2Aの同じ側から出射する。し
たがって、目盛板2Aから出射する＋１次回折光211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211及び212を干
渉させるハーフミラー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, the reflection type diffraction grating 16 is provided on the back side of the scale plate 2A.
Is formed, the laser beam 19 incident on the scale plate 2A
Are emitted as diffracted light from the same side of the scale plate 2A. Therefore, ± 1-order diffracted light 21 1 and 21 2 reflected by the mirror 8 1 and 8 2 and the mirror 8 1 and 8 2 respectively reflecting the + 1st emitted from the scale plate 2A diffracted light 21 and -1 order diffracted light 21 2 The half mirror 9 and the light receiving element 10 that interfere with each other are arranged on the same side as the laser diode 1.
反射型回折格子16での＋１次回折光の＋１次回折光20
1は で表わされ、−１次回折光の−１次回折光202は で表わされる。この＋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15により回
折され、その＋１次回折光211は 前記−１次回折光の−１次回折光202は、同様に目盛板2
A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 でそれぞれ表わされる。+ 1st-order diffracted light 20 of + 1st-order diffracted light on reflection type diffraction grating 16
1 is In expressed, -1, -1-order diffracted light 20 and second-order diffracted light Is represented by When the + 1st order diffracted light 20 1 of the + 1st-order diffracted light is emitted from the scale plate 2A, is diffracted by the transmission type diffraction grating 15, the + 1st-order diffracted light 21 1 The -1 order diffracted light 20 and second-order diffracted light is similarly scale 2
When emitted from A, is diffracted by the transmission type diffraction grating 15, the -1st-order diffracted light 21 2 Respectively.
式（２）（３）で各々表わされる２つの回折光211及
び212をハーフミラー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が、 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ピッチｐ移動すると、その明暗が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。When causing interference formula (2) (3) in each of two diffracted lights 21 1 and 21 2 represented by a half mirror 9, the interference light, the amplitude along the slide of the scale plate 2A, It changes as shown in the equation. That is, when the graduation of the graduation plate 2A moves by one pitch p in the X direction, the lightness and darkness are generated six times. The interference light 22 is detected by the light receiving element 10, and the output pulse is counted by the counter 11. The movement amount of the scale plate 2A is measured from the counted 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。(Effect of the Invention) Since the present invention is configured as described above, it has an effect that the movement amount of the object to be measured can be measured with higher accuracy than the conventional one.
第１図は参考例のエンコーダの全体構成を示す線図、第
２図は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 12……カウンタ 15……透過型回折格子 16……反射型回折格子FIG. 1 is a diagram showing the overall configuration of an encoder of a reference example, FIG. 2 is a diagram showing the overall configuration of an encoder of an embodiment of the present invention, and FIG. 3 is a diagram showing the overall configuration of a conventional encoder. is there. DESCRIPTION OF SYMBOLS 1 ... Laser diode 2, 2A ... Scale plate 4, 5 ... Transmission diffraction grating 11 ... Light receiving element 12 ... Counter 15 ... Transmission diffraction grating 16 ... Reflection diffraction grating
───────────────────────────────────────────────────── フロントページの続き (72)発明者 山田 英郎 神奈川県厚木市長谷字柳町260―63 株 式会社測機舎厚木工場内 (72)発明者 関口 保洋 神奈川県厚木市長谷字柳町260―63 株 式会社測機舎厚木工場内 (56)参考文献 特開 平２−231526（ＪＰ，Ａ) 特開 昭62−25212（ＪＰ，Ａ) 実開 平２−144719（ＪＰ，Ｕ) 特公 昭55−31882（ＪＰ，Ｂ２) ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Hideo Yamada 260-63 Yanagimachi, Hase, Atsugi-shi, Kanagawa Prefecture Inside the Sokkisha Atsugi Plant (72) Inventor Yasuhiro Sekiguchi 260, Yanagicho, Hase, Atsugi-shi, Kanagawa 63 Inside the Akkigi Factory of Sokkisha Co., Ltd. (56) References JP-A-2-231526 (JP, A) JP-A-62-2252 (JP, A) Showa 55-31882 (JP, B2)
Claims (2)
され、裏側に反射型回折格子が形成されていることを特
徴とする光学式エンコーダの目盛板。1. A scale plate for an optical encoder, wherein a transmission type diffraction grating is formed on a front side of a plate-shaped transparent plate, and a reflection type diffraction grating is formed on a back side.
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。2. A laser light source, a scale plate sliding across the front of the laser light source, optical means for interfering diffracted light formed by the scale plate, and a light receiving element for receiving the interference light; An optical encoder comprising a counter for counting output pulses of a light-receiving element, wherein the scale plate has a transmission-type diffraction grating formed on the front side of a plate-shaped transparent plate, and a reflection-type diffraction grating formed on the back side. An optical encoder, characterized in that:
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 JPH0481612A (en) | 1992-03-16 |
| JP3015962B2 true 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) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3158878B2 (en) * | 1994-07-28 | 2001-04-23 | 松下電器産業株式会社 | Optical encoder |
| WO2002023130A1 (en) * | 2000-09-13 | 2002-03-21 | Mitsubishi Denki Kabushiki Kaisha | Optical encoder |
| 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 |
| JP2005315649A (en) * | 2004-04-27 | 2005-11-10 | Sumitomo Heavy Ind Ltd | Detection device and stage device |
-
1990
- 1990-07-25 JP JP2194790A patent/JP3015962B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0481612A (en) | 1992-03-16 |
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