JPS59159016A - Optical encoder - Google Patents
Optical encoderInfo
- Publication number
- JPS59159016A JPS59159016A JP3326983A JP3326983A JPS59159016A JP S59159016 A JPS59159016 A JP S59159016A JP 3326983 A JP3326983 A JP 3326983A JP 3326983 A JP3326983 A JP 3326983A JP S59159016 A JPS59159016 A JP S59159016A
- Authority
- JP
- Japan
- Prior art keywords
- light
- slit
- receiving surfaces
- slits
- encoder
- 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.)
- Pending
Links
- 230000003287 optical effect Effects 0.000 title claims description 13
- 238000001514 detection method Methods 0.000 claims description 27
- 239000004065 semiconductor Substances 0.000 claims description 4
- 230000033001 locomotion Effects 0.000 abstract description 4
- 230000003321 amplification Effects 0.000 abstract description 2
- 238000003199 nucleic acid amplification method Methods 0.000 abstract description 2
- 230000001360 synchronised effect Effects 0.000 abstract description 2
- 238000006243 chemical reaction Methods 0.000 abstract 1
- 230000004907 flux Effects 0.000 abstract 1
- 238000010586 diagram Methods 0.000 description 4
- 238000000034 method Methods 0.000 description 4
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 3
- 238000009826 distribution Methods 0.000 description 2
- 238000000609 electron-beam lithography Methods 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000000428 dust Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000010894 electron beam technology Methods 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 1
- 239000010931 gold Substances 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 239000004575 stone Substances 0.000 description 1
- 239000000758 substrate Substances 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
- G01D5/347—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 using displacement encoding scales
- G01D5/34707—Scales; Discs, e.g. fixation, fabrication, compensation
- G01D5/34715—Scale reading or illumination devices
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optical Transform (AREA)
Abstract
Description
【発明の詳細な説明】 本発明は、光学エンコーダに関するものである。[Detailed description of the invention] The present invention relates to optical encoders.
従来より、エンコーダ本体に目盛としてトラック状に微
少スリットを形成し、検出用格子を介しで前記微少スリ
ットを透過する光ビームをホトダイオードへ照射させ、
エンコーダ本体の回転をホトダイオードの光学的変化と
して捕え、回転角全測定する所謂光電式ロータリエンコ
ーダが存在している。ところで、この光電式ロータリエ
ンコーダでは、高度の写真刻線技術を駆使して１回転４
３２００パルスから４ ａ ２０００ ハルスの分解能
のエンコーダも存在しているが、その回転角目盛の確度
が不明確であったりし、精度、信頼性の上で問題があっ
た。Conventionally, minute slits are formed in the shape of a track as graduations on the encoder body, and a photodiode is irradiated with a light beam that passes through the minute slits through a detection grating.
There is a so-called photoelectric rotary encoder that captures the rotation of the encoder body as an optical change in a photodiode and measures the entire rotation angle. By the way, this photoelectric rotary encoder makes full use of advanced photographic engraving technology to
Encoders with a resolution of 3200 pulses to 4 a 2000 Hals exist, but the accuracy of their rotational angle scales is unclear, and there are problems with accuracy and reliability.
本発明は、上述の従来技術の問題点を解消すべく、高精
度、尚確度、高信頼性を有する光学エンコーダを提供す
ること全目的とする。SUMMARY OF THE INVENTION It is an object of the present invention to provide an optical encoder having high precision, accuracy, and reliability in order to overcome the problems of the prior art described above.
以ド、本発明の一実施例を図面に従い説明する。Hereinafter, one embodiment of the present invention will be described with reference to the drawings.
エンコーダ本体ｌは、軸２を中心に回転可能であり、外
周部に前記軸２の中心Ｏを幾何学的中心とした第１トラ
ツク３と第２トラツク４が形成し２である。この第１、
第２トラツク３．４は、第２図に示すように、光不透過
部分５を主要部とするエンコーダ本体１に、同一分割数
の光学的な目盛となるように各光透過部分６を前記ｉｉ
＋１１１２の中心Ｏに対して張る角度が等しく、壕だ位
相を揃えて形成している。The encoder main body 1 is rotatable about a shaft 2, and has a first track 3 and a second track 4 formed on its outer periphery with the center O of the shaft 2 being the geometric center. This first,
As shown in FIG. 2, the second track 3.4 includes each light-transmitting part 6 on the encoder body 1, which has a light-opaque part 5 as its main part, so as to form an optical scale with the same number of divisions. ii
+1112 has the same angle with respect to the center O, and the grooves are formed with the same phase.
前記光透過部分６と光不透過部分５とからなる各トラン
ク３．４の形成は、電子計算機と電子ビーム描画装置を
使用して行う。一般に電子ビーム描画ができる領域はｌ
２０ｍｍＸ１１０ｍｍの領域のものであって、記録位
置精腿は０．１μｍである。依って、１本のトラック−
周の光透過部分６の数、つまり分割数を２１６００とす
ると、１つの光透過部分６が中心０に対して張る角度は
３０″になる。そして第１トラツク８の外径が１０７゜
２６ｍｍ、トランク幅０．５ｍｍであり、第２トラツク
４の外径が１０５．８６ｍｍ、トラック幅０．５ｍｍで
あると、光透過部分６の記録の空間波長は、第１トラン
ク３上で１５．６μｍ、第２トラツク４上で１５，４μ
ｍとなる。The formation of each trunk 3.4 consisting of the light-transmitting portion 6 and the light-opaque portion 5 is performed using an electronic computer and an electron beam lithography device. In general, the area where electron beam writing can be performed is l
The area is 20 mm x 110 mm, and the recording position is 0.1 μm. Therefore, one track -
If the number of light transmitting parts 6 on the circumference, that is, the number of divisions, is 21,600, the angle that one light transmitting part 6 makes with respect to the center 0 is 30''.The outer diameter of the first track 8 is 107°26 mm, If the trunk width is 0.5 mm, the outer diameter of the second track 4 is 105.86 mm, and the track width is 0.5 mm, the spatial wavelength of recording in the light transmitting portion 6 is 15.6 μm on the first trunk 3. 15,4μ on the second track 4
m.
上述のようなバクーンを有するエンコーダ原盤の製作工
程は、一般的な超ＬＳＩ用マスターマスクと全く同様で
あり、５″角クロムブランクス上にポジレジストを塗布
し、重子ビームにより指定個所（光透過部分）を露光し
、その部分を現像で溶かし、クロム地を露出させ、クロ
ムエツチング処理を施して、その露出部分のガラス基板
を露出し、透明化する。このようにして得られたエンコ
ーダ原盤の目盛となる光透過部分の仕上がり精度は、光
透過部分の位置誤差、形状誤差が０．１μｍ以下である
から、光透過部分の中心に対して張る角度誤差がｏ 、
Ｌ Ｈ以下になる。実際に使用きれるエンコーダ本
体は、このエンコーダ原盤からコピーしたものであるが
へそれでも略同等の精度は維持している。The manufacturing process of the encoder master with the above-mentioned backcoon is exactly the same as that of a general master mask for VLSI, in which a positive resist is applied on a 5" square chrome blank, and designated areas (light-transmitting areas) are ) is exposed to light, that part is melted by development, the chrome base is exposed, and a chrome etching process is performed to expose the exposed part of the glass substrate and make it transparent.The scale of the encoder master obtained in this way The finishing accuracy of the light transmitting part is that the positional error and shape error of the light transmitting part are less than 0.1 μm, so the angular error relative to the center of the light transmitting part is o,
It becomes below LH. The encoder body that can actually be used is a copy of this encoder master, but it still maintains approximately the same accuracy.
次に、前６己第１トラツク３と第２トラツク４とに対向
設置ばされる検出用格子７の構成を説明する。Next, the structure of the detection grating 7, which is disposed opposite to the first track 3 and the second track 4, will be explained.
第３図に検出用格子７の原理的構成を示す。この検出用
格子７は、具体的−例として同一ピッチの４７個の光透
過用のスリットＳからなる４個のスリット群８．９．１
Ｏ１１１′ｌｆ：形成しである０これらのスリット群８
．９．１０．１１は、前記第１トラツク３に対して２つ
のスリット群８．９を、また第２トラツク４に対して２
つのスリット群１０．１１を各々配列し、同一トランク
に配列されるスリット群は、互に空間位相で１８００の
差がある。さらに異なるトラックに配列されスリット群
の内、上下近接するスリット群８とｉｏとの間の空間位
相差は９００であり、スリット群９と１１との間の関係
も同様である。これらのスリット群８．９．１０，１１
のスリットＳの幾何学的中心は、第４図のように前記エ
ンコーダ本体１の＠３２の中心Ｏであり、谷スリット群
８．９．１０．１１のスリットＳが中ノｌＪＯに対して
張る角度は・エンコーダ本体１の光透過部分６と同じに
しである。従って、エンコーダ本体１の各トラック３．
４と、検出用格子７の各スリット群８．９．１Ｏ５１１
との幾何学的中心を一致をせて重ね合せると第４図に示
すようになり、スリット群８．９．１０．１１でそれぞ
ｒｌ、光透過する面積が異なっているので、透過ビーム
光量が変化する。FIG. 3 shows the basic configuration of the detection grating 7. This detection grating 7 is made up of, for example, four slit groups 8.9.1 consisting of 47 light-transmitting slits S with the same pitch.
O111'lf: These slit groups 8 are formed
．． 9.10.11 has two slit groups 8.9 for the first track 3 and two slit groups 8.9 for the second track 4.
Two slit groups 10 and 11 are each arranged, and the slit groups arranged in the same trunk have a spatial phase difference of 1800 degrees. Further, among the slit groups arranged in different tracks, the spatial phase difference between slit groups 8 and io that are close to each other above and below is 900, and the relationship between slit groups 9 and 11 is also the same. These slit groups 8.9.10,11
The geometric center of the slit S is the center O of @32 of the encoder body 1 as shown in FIG. The angle is the same as the light transmitting portion 6 of the encoder body 1. Therefore, each track 3 of the encoder body 1.
4 and each slit group 8.9.1O511 of the detection grating 7
When the geometric centers of the slits are aligned and superimposed, it becomes as shown in Fig. 4, and since the slit groups 8, 9, 10, and 11 have different rl and light transmitting areas, the amount of transmitted beam light is changes.
尚、上記検出用格子の説明にて、各スリット群８．９．
１０．１１のスリットＳの数才、４７個としだが、この
ように多数のスリットＳを使用する理由は、透Ａ元量を
大さくして検出信号のＳｌ□ｌ比を同上させるためと、
４７個のスリットＳの平均空間位相を検出することにな
るので、目盛となる光透過部分６に付いた傷あるいは塵
埃の＃響を小さくするためであるから、本発明としては
、前記スリット群に対応する丙所に最低各１本のスリッ
トＳを１′３己し、日干４１固のスリットがあれば良い
。In addition, in the above description of the detection grating, each slit group 8.9.
The number of slits S in 10.11 is 47, but the reason for using such a large number of slits S is to increase the amount of transmission A and increase the Sl□l ratio of the detection signal.
Since the average spatial phase of the 47 slits S will be detected, the purpose of this invention is to reduce the noise caused by scratches or dust on the light transmitting portion 6 that serves as a scale. It is sufficient to have at least one slit S in each corresponding location, and a slit with a diameter of 41 degrees.
上述の検出用格子７のスリット群８．９．１０．１１も
電子ビーム描画で精度よくできる上、スリノトイ片すノ
し状も一例として２．４ｍｍＸ３．６＋ｎ１Ｔｈと小さ
いため、従来一般的な工Ｃチップの描画方法と同様に、
同じスリットパターンをノｌ真次繰返し露光すれば良い
ので多数のスリン）Ｓがα子ビームＶこて一枚のマスク
上に描画できる。The slit groups 8.9.10.11 of the detection grating 7 described above can also be made with high accuracy by electron beam lithography, and the shape of the slits is small, for example, 2.4 mm x 3.6 + n1 Th, so it is possible to use the conventional common process C. Similar to how the chip is drawn,
Since the same slit pattern can be repeatedly exposed every time, a large number of slits can be drawn on one mask of the α-beam V trowel.
次に、回転角の検出方法について説明する。。Next, a method of detecting the rotation angle will be explained. .
第１図及び第５図に示すように、スリット群８．９．１
０．１１全面に、発光ダイオード、ガスレーザあるいｒ
よ半導体レーザ尋の央負旧に平行光を元する光源１２よ
り発せられる元ビーム１３を一様に照射しくただし、実
際的には光源として半導体レーザを使用するのが種々の
点で望ましい）、各スリット群の極く近傍に明暗スリッ
ト像を形成する。このスリット像形成面上を、エンコー
ダ本体１のトラック３．４が走るようにし２、前記スリ
ット群８．９．１Ｏ１１１と第１１第２トラツク３．４
とは物理的に接触烙せない０、そして前記トランク３．
４を透過した４本の光束は、それぞね４個のスリット＃
８．９．１０．１１に対向設置Ｉ、また４個の受光面Ｄ
＋ 、 Ｄ２、Ｄｓ、Ｄ４ を刊する４分割ホトダイ
オード１４で光電変換させ、各トラ・ツクに対応する受
光面Ｄ＋ とＤ２、受光面Ｄ３ とＤ４との差動増
巾で（ｅ＋ 及び０２ を得る。従って、破測定物
の回転とエンコーダ本体ｌの回転を同期させておけば、
前記出力ｅｌ、０２ Ｋでトラック３．４の動きを検知
できるので公知のごとく回転角が・演出さｆ″Ｌろ。前
記４個の受光面を有するホトダイオードは一つのパッケ
ージに収納する４分割型ホトダイオード１４が好ましい
。As shown in Figures 1 and 5, slit group 8.9.1
0.11 Light emitting diode, gas laser or r
The original beam 13 emitted from the light source 12 originating from parallel light is uniformly irradiated at the center of the semiconductor laser beam; however, in practice, it is desirable from various points of view to use a semiconductor laser as the light source). Bright and dark slit images are formed very close to each slit group. The track 3.4 of the encoder main body 1 runs on this slit image forming surface 2, and the slit group 8.9.1O111 and the 11th second track 3.4
0, which cannot be physically touched, and the trunk 3.
The four beams of light that have passed through #4 pass through four slits #
8.9.10.11 Opposing installation I, and 4 light receiving surfaces D
+, D2, Ds, D4 are photoelectrically converted by the four-divided photodiode 14, and by differential amplification between the light-receiving surfaces D+ and D2 and the light-receiving surfaces D3 and D4 corresponding to each track, (e+ and 02 are obtained. Therefore, if the rotation of the broken object and the rotation of the encoder body l are synchronized,
Since the movement of the track 3.4 can be detected with the outputs el and 02 K, the rotation angle is increased as is known. Photodiode 14 is preferred.
前ｄ己スリット群とトラックの間隙２がある範囲でない
と、例えば本実施例においては、約１００μｍ以−ドの
間隙でないとスリシトＳに対応する像が明瞭に形成膓れ
ない。従って、トラックとスリット群を上記間隙範囲内
まで接近させてエンコーダ本体１を走らせることにより
、トラック３．４を透過した光束は、エンコーダ本体ｌ
の動きに対応して変動することになる０
向、スリットＳにより回折が生じるが、この回折光は平
面波であって、スリットＳによる伽幅変調は受けない。Unless the gap 2 between the front slit group and the track is within a certain range, for example, in this embodiment, the image corresponding to the slit S cannot be clearly formed unless the gap is about 100 μm or more. Therefore, by running the encoder body 1 with the tracks and slits close to each other within the above-mentioned gap range, the light beam transmitted through the tracks 3.4 is transmitted through the encoder body l.
Although diffraction occurs due to the slit S in the 0 direction which changes in response to the movement of the slit S, this diffracted light is a plane wave and is not subjected to the width modulation by the slit S.
才だ、エンコーダ本体１の目盛部分６を透過し、たレー
ザの光束は、第５図の破ｍＡにて示すようＶＣ回折する
ため±１次回折元までを、そね、それ対応する４分割型
ホトダイオード１４の受光面で父光させれば、他の受光
面へのクロスト−りを少なくすると共に検出信号のＢＮ
比を向上できる。The laser beam that passes through the scale part 6 of the encoder body 1 undergoes VC diffraction as shown in Fig. 5, so it is divided into four parts corresponding to the ±1st-order diffraction source. By transmitting light on the light receiving surface of the type photodiode 14, crosstalk to other light receiving surfaces can be reduced and the BN of the detection signal can be reduced.
ratio can be improved.
捷た、前記エンコーダ本体ｌの反り、または軸受部のガ
タ付き等により、前記検出用格子７との間隙Ｚが変動す
るため、その変動に対応できるように予め両者を離して
おく必要がある０従って、第７図に示すスリット群とス
リット像の光強度分布との関係のように、検出光出力に
はかなりの定常成分が重畳し、４分割型ホトダイオード
１４の各受光面からの検出信号に直流成分が重畳してく
る。この直流成分′を消去するために、本実施例では同
一トランクに配列されるスリット群、例えばスリット群
８と９、及びスリット群１０と１１とに空間位相差を１
８−００とり、スリット群８と９とにそれぞれ対向する
４分割型ホトダイオード１４の受光面り、とＤ２ 、
及びスリット群１０と１１とにそれぞれ対向する受光面
Ｄ３ とＤ４ との差動増巾をしている。特に、一
般的にホトダイオードは温度特性によるドリフトが多い
が、４分割型ホトダイオード１４のように同一パッケー
ジ内に受光面Ｄ＋ 、Ｄａ 、Ｄｓ 、Ｄ４
’に収納しであると、コンパクトに構成できると共に、
同一条件下に受光面が存在するため温度特性によるドリ
フト及びホトダイオードの暗電流等を互に打ち消すこと
ができる。Because the gap Z with the detection grating 7 changes due to warpage of the encoder main body l, warping of the encoder body l, or play in the bearing part, it is necessary to separate the two in advance to accommodate the fluctuation. Therefore, as shown in the relationship between the slit group and the light intensity distribution of the slit image shown in FIG. DC components are superimposed. In order to eliminate this DC component, in this embodiment, a spatial phase difference of 1 is set between slit groups arranged in the same trunk, for example, slit groups 8 and 9, and slit groups 10 and 11.
8-00, the light receiving surface of the four-part photodiode 14 facing the slit groups 8 and 9, and D2,
And the differential width of the light receiving surfaces D3 and D4 facing the slit groups 10 and 11, respectively, is increased. In particular, photodiodes generally have a lot of drift due to temperature characteristics, but as in the 4-segment photodiode 14, light-receiving surfaces D+, Da, Ds, D4 are arranged in the same package.
If it is stored in ', it can be configured compactly and
Since the light-receiving surfaces exist under the same conditions, drift due to temperature characteristics, dark current of the photodiode, etc. can be mutually canceled out.
ここで、上述した実施例では、４個の受光面を１つのパ
ッケージに収納″Ｊ７る４分割ホトダイオードを使用し
て説明し７たが、前述の差動出力を取る受光［Ｒ１２個
を１組としたパンケージとすることも考えられ、この場
合、パッケージ２個にて４個の受光面が得られろことに
なる。Here, in the above-mentioned embodiment, explanation was given using a 4-split photodiode in which 4 light-receiving surfaces are housed in one package. It is also conceivable to use a pan-cage with 2 packages, and in this case, 4 light-receiving surfaces can be obtained with 2 packages.
丑た、スリット群８とｌｏ、及びスリット群９と１１は
空１昌１的に正確に９００の位相差をもたせであるので
、例えば、前＾己検出用格子７の中心を通り、かつ光ビ
ーム１３の光軸と平行な軸を回転軸として、検出用格子
７全体全微少回転して調整すること（でより、検出信号
ｅ、と０２ の位相差を正確に９００に調整できる。Furthermore, since the slit groups 8 and 10 and the slit groups 9 and 11 have a phase difference of exactly 900, for example, the light passes through the center of the self-detecting grating 7, and the light Adjustment is made by slightly rotating the entire detection grating 7 using an axis parallel to the optical axis of the beam 13 as the rotation axis (thereby, the phase difference between the detection signals e and 02 can be adjusted to exactly 900 degrees.
従って第８図に示すようシこ検出１昌号１：’＋ ｙ
ｅ２ に振ｉ陥変動があっても、ゼロクロス時刻、
例えば検出信号ｅ１ に関しては波形Ｐ、 で示す
ようにｔ Ｉｏ 、’Ｌ ＋１．Ｔ： ＋ｚ ’−−−
−−−−−−がコンパレータ寺で正確に検出できる。、
険出信号ｅ２シ（付いても同様である。従って、分割敢
２１６００、すなわち１分割当り角度１′の場合でも、
その４分の１− Ｔ ｉわち１５″を最小升別率位にで
きることになる。Therefore, as shown in FIG.
Even if there is a fluctuation in e2, the zero crossing time,
For example, regarding the detection signal e1, the waveform P is t Io , 'L +1. T: +z'---
−−−−−− can be detected accurately using a comparator. ,
The same applies even if the start signal e2 is attached. Therefore, even if the division is 21600, that is, the angle per division is 1',
One-fourth of that - T i , ie, 15'' can be made into the minimum square rate.
さらに、検出信号θ１ 、ｅ２ の振幅は、エンコーダ
本体ｌの反り等で変動するが、この変動の予想ができる
ためデジタルメモリ等で回転角度毎の検出信号をメモリ
（〜でおき、常に一定振幅の検出信号ｅ、及びｅ２
になるように補正でき、ベクトルスコープ式に電子的に
１０倍から２０倍程度、さらに分割数を上げることがで
きる。Furthermore, the amplitudes of the detection signals θ1 and e2 fluctuate due to warping of the encoder body l, etc., but since this fluctuation can be predicted, the detection signals for each rotation angle are stored in a digital memory (~), and the amplitude is always constant. Detection signals e and e2
The number of divisions can be further increased by about 10 to 20 times electronically using a vector scope method.
また、エンコーダ本体ｌの目盛部分６の稍度がｏ、ｉ″
に仕上っていても、そのパターンの幾伺字的中心と、エ
ンコーダ本体ｌの回転中心にずれ、すなわち偏心がある
と測定角の確度が低下する。In addition, the degree of consistency of the scale portion 6 of the encoder body l is o, i″
Even if it is finished, if there is a deviation between the geometrical center of the pattern and the center of rotation of the encoder body l, that is, eccentricity, the accuracy of the measurement angle will decrease.
この偏心調整にはエンコーダ本体１を回転させ、トラン
クの外縁または内縁のゆらぎ、すなわち偏心を顕微鏡で
観測Ｉ〜、エンコータ゛本体１全周でｌｌｍＰＰ以内に
偏心を調整できれば、測定角の確度は、エンコーダ本体
ｌの直径１００ｍｍの場合、±２″程度に抑制できる〇
上述の実施例において、第３図に示すように、同一トラ
ックに配列されるスリット群は、互に空間位相で１８０
０の差を持ち、また異なるトラックに配列されたスリッ
ト群の内、上下近接するスリット群間の空間位相差が９
００あるようにし、同一トランク上に配列されたスリッ
ト群に対向する４分割型ホトダイオード１４の受光ｍＤ
＋ とＤ２、及び受光面Ｄ３ とＤ４ との差動出
力を得、しかもこの差動出力から回転角を測定している
が、上記配＋１．構成に限定きれるものでＶよなく、例
えば、同一トラック上に配置されるスリット群の空間位
相は一ト述の実施例と同一にし、エンコーダ本体ｌのト
ラックを形成する目盛となる光透過部分６を、第１トラ
ツク３と第２トラツク４において互に空間位相ｖＣ９０
０差があるようにし、検出用格子７の上ド近接するスリ
ット群８とＩＯ，及びスリット群９と１１との空間位相
差金００にしても同一作用効果が得られる。To adjust the eccentricity, rotate the encoder body 1 and observe the fluctuation of the outer or inner edge of the trunk, that is, the eccentricity, with a microscope. If the diameter of the main body l is 100 mm, it can be suppressed to about ±2''. In the above embodiment, as shown in FIG.
0, and among slit groups arranged on different tracks, the spatial phase difference between adjacent slit groups above and below is 9.
00, and the light reception mD of the four-segment photodiode 14 facing the slit group arranged on the same trunk.
+ and D2, and the light-receiving surfaces D3 and D4, and the rotation angle is measured from this differential output, but the above arrangement +1. For example, the spatial phase of the slit groups arranged on the same track is the same as in the above-mentioned embodiments, and the light-transmitting portion 6 that becomes the scale forming the track of the encoder main body 1 is used. The spatial phase vC90 of the first track 3 and the second track 4 is mutually
The same effect can be obtained even if the spatial phase difference between the slit groups 8 and IO and the slit groups 9 and 11 which are close to each other on the top of the detection grating 7 is set to 00.
なお、上述の実施例では、トラックを２本として説明し
たが、トランクを１本にし、そのトラックに対し、検出
用格子７のスリットと４分割型ホトダイオード１４の受
光面とを並列に配すようにすることも考えられる。In the above-mentioned embodiment, the explanation was given using two tracks, but it is also possible to use one trunk and arrange the slits of the detection grating 7 and the light receiving surface of the four-segment photodiode 14 in parallel with the track. It is also possible to do so.
このように、本発明の実施例として種々のトラック３．
４、検出用格子７、ホトダイオード１４の配置構成が考
えられるが、要するに、４分割型ホトダイオード１４０
４個の受光面Ｄ１、Ｄ２ 、ＤＢ 、Ｄ４ の内
、差動出力を取る１対の受光面からの谷出力波の位相を
１８００ずらせ、さらに検出信号ｅｌ 、 ２ 、すな
わち、差動出力波の位相を互に９００ずらすように、＄
）ラック３１．１＃亙△輩坦
４と４個のスリット群８．９．１０．１１とが配置構成
されていｆ’Ｌば良い。Thus, as an embodiment of the present invention, various tracks 3.
4. Although the arrangement configuration of the detection grating 7 and the photodiode 14 is conceivable, in short, the four-segment photodiode 140
Among the four light receiving surfaces D1, D2, DB, and D4, the phase of the valley output wave from a pair of light receiving surfaces that take differential output is shifted by 1800, and the detection signal el,2, that is, the differential output wave is so that the phases are shifted by 900 from each other, $
) Rack 31.1 # 躙△至面4 and four slit groups 8.9.10.11 are arranged and configured f'L is sufficient.
上述のように本発明は構成してなるため、特にエンコー
ダ本体に形成した券本寺トラックと、検出用格子に形成
した４個のスリット←と、４個の受光面を→砿傘１１遥
−−輌・ホトダイオード金使′用して、高祠度、高＃′
度、高信頼性を有する光学エンコーダを提供することが
できる。Since the present invention is configured as described above, in particular, the sensor track formed on the encoder body, the four slits formed on the detection grid, and the four light receiving surfaces are High purity and high #' by using gold photodiode
Therefore, it is possible to provide an optical encoder with high reliability.
第１図は本発明の一実施例の概略説明図、゛第２図は同
実施例のエンコーダ本体の要部拡大図、第３図は同実施
例の検出用格子の要部拡大図、第４図はエンコーダ本体
と検出用格子との関係を示す説明図、第５図は同実施例
の作用の説明図、第６図は４分割型ホトダイオードの上
面図、第７図はスリット群とスリット像の光強度分布と
の関係を示す説明ｔｇ＋ 、第８図は検出信号波形を示
す説明図である。
１・・エンコータ゛本体、３・・第１トラツク、４・・
第２トラツク、６・・目盛、７・・検出川石１ （゛
、 ８ 、 ９ 、 １０，１１ ・ ・ ス
リ ） ト 群 、 ｌ ２・・半導体レーザ
、１４・−４分割ホトダイオード、Ｊ）１ 、Ｄ２
、Ｄ３ 、Ｄ４ ” ”受光面、ｅｌ 、ｅ２
・・左動出力、Ｓ・・スリット。
特許用７９ｆ４人
萬世工業株式会社（他１名）
第１図
第２図
第３図
第５図FIG. 1 is a schematic explanatory diagram of an embodiment of the present invention, FIG. 2 is an enlarged view of the main part of the encoder main body of the same embodiment, FIG. 3 is an enlarged view of the main part of the detection grating of the same embodiment, Fig. 4 is an explanatory diagram showing the relationship between the encoder body and the detection grating, Fig. 5 is an explanatory diagram of the operation of the same embodiment, Fig. 6 is a top view of a four-segment photodiode, and Fig. 7 is a slit group and a slit group. Explanation tg+ showing the relationship with the light intensity distribution of the image, FIG. 8 is an explanatory diagram showing the detection signal waveform. 1. Encoder body, 3. 1st track, 4.
2nd track, 6...Scale, 7...Detection river stone 1 (゛
, 8, 9, 10, 11... Suri) To group, L 2... Semiconductor laser, 14... -4 division photodiode, J) 1, D2
, D3, D4 "" light-receiving surface, el, e2
...Left motion output, S...slit. Patent 79f4 Jinmansei Kogyo Co., Ltd. (1 other person) Figure 1 Figure 2 Figure 3 Figure 5
Claims (1)
ンクを形成したエンコーダ本体と、スリット４個を有し
、かつ前記トラックに対して配設する検出用格子と、こ
の検出用格子に実質的平行光を与える光源と、前記４個
のスリットに対向した４個の受光面にて、前記トランク
及びスリットを透過する４本の光束を各々独立して受光
し、かつ前ηピ４個の受光面の内、少なくとも２個を１
組とするホトダイオードとからなり、このホトダイオー
ドの受光面の内、組となる受光面からそれぞれ差動出力
を取り、この組となる受光面からの各出力波の位相を１
８ｏＯずらせ、さらに２組の受光面からの各差動出力波
の位相を互に９００ずらせるようＫ ｉ７） ｉ己目盛
とスリットを設けたこと全特徴とする光学エンコーダ。 ２ 前記トラックを複数本にした特許請求の範囲第１項
記載の光学エンコーダ。 ３、 前記各スリットを、それぞれピッチが等しい複数
のスリットから構成したスリット群とした特許請求の範
囲第１項記載の光学エンコーダ。 ４、 前記光源を半導体レーザーとした特許請求の範囲
第１項記載の光学エンコーダ。 ５、 前記ホトダイオードを４個の受光面が１パツケー
ジとなる４分割型ホトダイオードとした特許請求の範囲
第１項記載の光学エンコーダ０ ６、 前記エンコーダ本体の目盛と、検出用格子のスリ
ットを電子ビーム描画装置にて形成した特許請求の範囲
第１項記載の光学エンコーダ０[Scope of Claims] 1. An encoder main body forming at least one trunk provided with a scale of the same number of divisions, a detection grid having four slits and disposed with respect to the track, and A light source that provides substantially parallel light to the detection grating and four light receiving surfaces facing the four slits independently receive the four beams of light that pass through the trunk and the slits, and At least two of the four light-receiving surfaces of η
It consists of a set of photodiodes, which take differential outputs from each of the light-receiving surfaces of the photodiodes, and set the phase of each output wave from the light-receiving surfaces of this set to 1.
An optical encoder having a K i7) i scale and a slit so as to shift the phase of each differential output wave from the two sets of light receiving surfaces by 800 and further shift the phase of each differential output wave from the two sets of light receiving surfaces by 900. 2. The optical encoder according to claim 1, wherein the number of tracks is plural. 3. The optical encoder according to claim 1, wherein each of the slits is a slit group consisting of a plurality of slits each having an equal pitch. 4. The optical encoder according to claim 1, wherein the light source is a semiconductor laser. 5. The optical encoder according to claim 1, wherein the photodiode is a 4-segment photodiode in which four light-receiving surfaces form one package. Optical encoder 0 according to claim 1 formed using a drawing device
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3326983A JPS59159016A (en) | 1983-03-01 | 1983-03-01 | Optical encoder |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3326983A JPS59159016A (en) | 1983-03-01 | 1983-03-01 | Optical encoder |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS59159016A true JPS59159016A (en) | 1984-09-08 |
Family
ID=12381801
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3326983A Pending JPS59159016A (en) | 1983-03-01 | 1983-03-01 | Optical encoder |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS59159016A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1987005693A1 (en) * | 1986-03-14 | 1987-09-24 | Mitutoyo Mfg. Co., Ltd. | Photoelectric displacement detector |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5232380A (en) * | 1975-09-05 | 1977-03-11 | Yaskawa Electric Mfg Co Ltd | Photoelectric type revolution speed detector |
| JPS5263747A (en) * | 1975-11-20 | 1977-05-26 | Fujitsu Ltd | Light detector for optical encoder |
| JPS557648A (en) * | 1978-07-04 | 1980-01-19 | Canon Inc | Photo encoder |
| JPS57111509A (en) * | 1980-12-29 | 1982-07-12 | Nippon Telegr & Teleph Corp <Ntt> | Fine space positioning device of information retrieval device |
-
1983
- 1983-03-01 JP JP3326983A patent/JPS59159016A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5232380A (en) * | 1975-09-05 | 1977-03-11 | Yaskawa Electric Mfg Co Ltd | Photoelectric type revolution speed detector |
| JPS5263747A (en) * | 1975-11-20 | 1977-05-26 | Fujitsu Ltd | Light detector for optical encoder |
| JPS557648A (en) * | 1978-07-04 | 1980-01-19 | Canon Inc | Photo encoder |
| JPS57111509A (en) * | 1980-12-29 | 1982-07-12 | Nippon Telegr & Teleph Corp <Ntt> | Fine space positioning device of information retrieval device |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1987005693A1 (en) * | 1986-03-14 | 1987-09-24 | Mitutoyo Mfg. Co., Ltd. | Photoelectric displacement detector |
| US4840488A (en) * | 1986-03-14 | 1989-06-20 | Mitutoyo Mfg. Co., Ltd. | Photoelectric type displacement detecting instrument |
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