JPH0321849B2 - - Google Patents
Info
- Publication number
- JPH0321849B2 JPH0321849B2 JP11124080A JP11124080A JPH0321849B2 JP H0321849 B2 JPH0321849 B2 JP H0321849B2 JP 11124080 A JP11124080 A JP 11124080A JP 11124080 A JP11124080 A JP 11124080A JP H0321849 B2 JPH0321849 B2 JP H0321849B2
- Authority
- JP
- Japan
- Prior art keywords
- light
- laser beam
- pattern
- diffraction image
- rotational movement
- 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
- 238000000034 method Methods 0.000 claims description 9
- 239000000758 substrate Substances 0.000 claims description 9
- 238000010586 diagram Methods 0.000 description 5
- 238000001514 detection method Methods 0.000 description 3
- 239000004065 semiconductor Substances 0.000 description 3
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 239000010979 ruby Substances 0.000 description 1
- 229910001750 ruby Inorganic materials 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
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optical Transform (AREA)
Description
【発明の詳細な説明】
本発明は回転移動量の新規な検出方法に関して
いる。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel method for detecting the amount of rotational movement.
従来、回転移動量を検出する方法として回転形
エンコーダが知られているが、これは例えば第１
図に示している様に透明円板１を入力軸２に取り
つけ、透明円板上に印刷した不透明部分と透明な
部分との模様を光電素子３で照射し、これを受光
素子４に受けて、その回転量を一定単位のデジタ
ル信号値に変換して検出するもので、サーボシス
テムの検出器として用いられており、パルスモー
タによるステージ移動の検出などに応用されてい
る。 Conventionally, a rotary encoder is known as a method for detecting the amount of rotational movement.
As shown in the figure, a transparent disk 1 is attached to an input shaft 2, a pattern of opaque and transparent areas printed on the transparent disk is irradiated with a photoelectric element 3, and the light is received by a light receiving element 4. , which detects the amount of rotation by converting it into a digital signal value of a fixed unit.It is used as a detector in a servo system, and is applied to detect stage movement by a pulse motor.
本発明はこの様な従来の光電式による検出方法
より更に精度が向上できる回転移動量の検出方法
を提案するもので、本発明の特徴は、半径方向の
環幅を円周方向に連続して徐々に変化させた形状
であつてレーザ光が透過する円環パターンを有す
る回転基板を設け、該基板に対してレーザ光を照
射して該円環パターンの透過レーザ光の回折像を
得、該回折像間の距離を求めることにより、該回
転基板の回転移動位置を検出する方法で、以下詳
細に説明する。 The present invention proposes a method for detecting the amount of rotational movement that can further improve accuracy than such conventional photoelectric detection methods. A rotating substrate having a circular pattern whose shape is gradually changed and through which laser light is transmitted is provided, the substrate is irradiated with a laser beam to obtain a diffraction image of the transmitted laser beam of the circular pattern, and the laser beam is transmitted through the circular pattern. The method of detecting the rotational movement position of the rotating substrate by determining the distance between the diffraction images will be described in detail below.
レーザ光は公知の様に1〓m前後又は精々10〓m程
度の波長をもつた光で、半導体レーザの他にルビ
ーレーザ、YGAレーザなどの固体レーザや炭酸
ガスレーザなどの気体レーザと多種類があるが、
この様なレーザ光は多数の波長の光が合成された
可視光線とは異なり、単波長的な光で干渉性が高
いために回折像が得られ易い性質の光である。例
えば第２図に示している様に狭いスリツト５にレ
ーザ光を投射すると、スリツトを通してレーザ光
源とは反対位置のスクリーン上に回折像６が現わ
れるが、その光強度分布７は右に図示している様
に０次光、１次光、２次光となるに従つて弱くな
る。且つ、これらの間隔例えば０次光と１次光と
の距離ｄは第３図の光強度分布７に示している様
にスリツト間隙Ｌに逆比例しており、ｄ∝λ／Ｌ
（λ：レーザ光の波長）なる関係にあつて、スリ
ツト５の広い間隙L1を透過したレーザ光の回折
像６間の距離d1は狭く、狭い間隙L2を透過したレ
ーザ光の回折像間の距離d2は広くなる。 As is well known, laser light has a wavelength of around 1〓 m or at most 10〓 m , and there are many types of laser light, including semiconductor lasers, solid-state lasers such as ruby lasers and YGA lasers, and gas lasers such as carbon dioxide lasers. Yes, but
Unlike visible light, which is a combination of multiple wavelengths of light, such laser light is a single-wavelength light that has high coherence, making it easy to obtain a diffraction image. For example, when laser light is projected onto a narrow slit 5 as shown in FIG. 2, a diffraction image 6 appears through the slit on the screen opposite to the laser light source, and its light intensity distribution 7 is shown on the right. The light becomes weaker as it becomes 0th order light, 1st order light, and 2nd order light. Moreover, the distance between these, for example, the distance d between the 0th-order light and the 1st-order light, is inversely proportional to the slit gap L, as shown in the light intensity distribution 7 in FIG. 3, and d∝λ/L.
(λ: wavelength of the laser beam), the distance d 1 between the diffraction images 6 of the laser beam transmitted through the wide gap L 1 of the slit 5 is narrow, and the diffraction image of the laser beam transmitted through the narrow gap L 2 The distance d 2 between them becomes wider.
本発明はこの様なスリツト間隙Ｌと回折像の距
離ｄとが逆比する関係を利用して、移動量を測る
方法で、直線方向の移動位置を測ることもできる
が、本発明では特に回転方向の移動位置を測る方
法の提案である。そのために、上記のスリツト間
隙に代えて、第４図に示す様に、透明基板８上に
金属膜で遮蔽部分を形成し、レーザ光を透過させ
る透明部分を環巾が円周方向に連続して変わる円
環パターン９に形成し、その円環の半径を約10mm
環巾の最も広い巾を100μm、最み狭い巾は０とす
る。この様な円環パターンはフオトプロセスを用
いて、半導体装置用のフオトマスクと同様に高精
度に形成できる。 The present invention utilizes the inverse ratio relationship between the slit gap L and the distance d of the diffraction image to measure the amount of movement, and the position of movement in the linear direction can also be measured. This is a proposal for a method to measure the position of movement in the direction. For this purpose, instead of the above-mentioned slit gap, a shielding part is formed with a metal film on the transparent substrate 8, as shown in FIG. A ring pattern 9 is formed that changes depending on the direction of the ring, and the radius of the ring is approximately 10 mm.
The widest ring width is 100 μm, and the narrowest width is 0. Such an annular pattern can be formed with high precision using a photo process, similar to a photomask for semiconductor devices.
この様なレーザ光を透過する円環パターン９を
形成した基板８の中心位置を第５図に示す様に測
定せんとする入力回転軸１０に取り付け、レーザ
発振器１１より出たレーザビームをレーズ系から
なるエツクスパンダー１２によりビーム径を調節
して直径約200μmのレーザビームとして、円環パ
ターン９に投射する。そして、レーザ発振器とは
反対側に、Ｘ方向（横方向）にのみエレメントを
配列した例えば半導体素子からなるイメージセン
サ１３を配置し、該イメージセンサにより円環パ
ターンを透過して形成された回折像を受光する。
イメージセンサは巾10μm程度のエレメントをＸ
方向に約1000ケ並べ、その全長は10mmとなるが、
そのエレメントに回折像を受光し、回折像の距離
をエレメントの受光により検出して、上記のＬと
ｄとは逆比例する関係から円環パターンの巾を求
め、最も広い100μmの円環巾をもつた位置からど
れだけ回転移動したかその移動位置を知ることが
できる。勿論、レーザ発振器１１とイメージセン
サ１３とは回転する円環パターンを通して正確に
位置合せして固定せしめる。 The center position of the substrate 8 on which the annular pattern 9 that transmits the laser beam is formed is attached to the input rotating shaft 10 to be measured as shown in FIG. The beam diameter is adjusted by an expander 12, and a laser beam with a diameter of about 200 μm is projected onto the annular pattern 9. Then, on the opposite side from the laser oscillator, an image sensor 13 made of, for example, a semiconductor element with elements arranged only in the X direction (lateral direction) is arranged, and a diffraction image formed by transmitting the annular pattern by the image sensor receives light.
The image sensor uses an element with a width of about 10μm
Approximately 1000 pieces are lined up in the direction, and the total length is 10 mm.
A diffraction image is received by the element, the distance of the diffraction image is detected by the light reception of the element, and the width of the annular pattern is determined from the relationship that L and d are inversely proportional to each other, and the widest annular width of 100 μm is determined. You can know how much rotation has been made from the tangled position. Of course, the laser oscillator 11 and the image sensor 13 are accurately aligned and fixed through the rotating annular pattern.
以上が実施法の説明であるが、この様な本発明
の方法は回転パターンとイメージセンサとの距離
を加減し、レンズ系をその間に挿入して回折像を
大きく拡大する等の処置を施せば、リニヤ・スケ
ールのために更に精度を上げることができる。一
方、第１図に示している従来の回転形エンコーダ
では光を透過する透明円板のビツト単位の模様に
限界が生ずるので、回転移動精度もその模様によ
り限定されることになる。 The above is an explanation of the implementation method, but the method of the present invention can be achieved by adjusting the distance between the rotating pattern and the image sensor, inserting a lens system between them, and greatly enlarging the diffraction image. , the accuracy can be further increased due to the linear scale. On the other hand, in the conventional rotary encoder shown in FIG. 1, there is a limit to the bit-by-bit pattern of the transparent disk that transmits light, so the accuracy of rotational movement is also limited by the pattern.
この様に本発明はパルスモータなどを用いてス
テージ移動を行なう場合に、その制御精度を一層
良くする検出方法で、自動調節装置を高精度とす
るのに大きく役立つものである。 As described above, the present invention is a detection method that further improves the control accuracy when moving a stage using a pulse motor or the like, and is greatly useful in making an automatic adjustment device highly accurate.
第１図は従来の回転形エンコーダの説明図、第
２図及び第３図は本発明の原理を説明する図、第
４図は本発明に応用する円環パターン図、第５図
は本発明の検出方法を示す図である。
図中、１は透明円板、２は入力軸、３は光電素
子、４は受光素子、５はスリツト、６は回折像、
７は回折像の光強度分布、８は透明基板、９は円
環パターン、１０は入力回転軸、１１はレーザ発
振器、１２はエックスパンダ、１３はイメージセ
ンサを示す。
Fig. 1 is an explanatory diagram of a conventional rotary encoder, Figs. 2 and 3 are explanatory diagrams of the principle of the present invention, Fig. 4 is an annular pattern diagram applied to the present invention, and Fig. 5 is a diagram of the present invention. FIG. 2 is a diagram showing a detection method. In the figure, 1 is a transparent disk, 2 is an input shaft, 3 is a photoelectric element, 4 is a light receiving element, 5 is a slit, 6 is a diffraction image,
7 is a light intensity distribution of a diffraction image, 8 is a transparent substrate, 9 is an annular pattern, 10 is an input rotation axis, 11 is a laser oscillator, 12 is an expander, and 13 is an image sensor.
Claims (1)
変化させた形状であつてレーザ光が透過する円環
パターンを有する回転基板を設け、該基板に対し
てレーザ光を照射して該円環パターンの透過レー
ザ光の回折像を得、該回折像間の距離を求めるこ
とにより、該回転基板の回転移動位置を検出する
ことを特徴とする回転移動量の検出方法。1. A rotating substrate is provided which has a ring pattern in which the ring width in the radial direction is continuously and gradually changed in the circumferential direction and through which a laser beam passes, and the substrate is irradiated with a laser beam to A method for detecting the amount of rotational movement, characterized in that the rotational movement position of the rotating substrate is detected by obtaining a diffraction image of a transmitted laser beam in an annular pattern and determining the distance between the diffraction images.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11124080A JPS5735715A (en) | 1980-08-13 | 1980-08-13 | Detection of rotating movement |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11124080A JPS5735715A (en) | 1980-08-13 | 1980-08-13 | Detection of rotating movement |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5735715A JPS5735715A (en) | 1982-02-26 |
| JPH0321849B2 true JPH0321849B2 (en) | 1991-03-25 |
Family
ID=14556124
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP11124080A Granted JPS5735715A (en) | 1980-08-13 | 1980-08-13 | Detection of rotating movement |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5735715A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5376785A (en) * | 1992-10-02 | 1994-12-27 | Chin; Philip K. | Optical displacement sensor utilizing optical diffusion |
-
1980
- 1980-08-13 JP JP11124080A patent/JPS5735715A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5735715A (en) | 1982-02-26 |
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