WO2016171108A1 - Reflective encoder - Google Patents

Reflective encoder Download PDF

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Publication number
WO2016171108A1
WO2016171108A1 PCT/JP2016/062299 JP2016062299W WO2016171108A1 WO 2016171108 A1 WO2016171108 A1 WO 2016171108A1 JP 2016062299 W JP2016062299 W JP 2016062299W WO 2016171108 A1 WO2016171108 A1 WO 2016171108A1
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Prior art keywords
diffraction grating
encoder
light receiving
light
code wheel
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PCT/JP2016/062299
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French (fr)
Japanese (ja)
Inventor
廉士 澤田
中村　元一
正紀 石川
久郷　智之
千尋 岡本
英雄 會田
智英 青柳
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並木精密宝石株式会社
アダマンド株式会社
廉士 澤田
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Publication of WO2016171108A1 publication Critical patent/WO2016171108A1/en

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    • 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
    • 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
    • G01D5/38—Forming the light into pulses by diffraction gratings
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/02—Details
    • H01L31/0232—Optical elements or arrangements associated with the device
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/12—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof structurally associated with, e.g. formed in or on a common substrate with, one or more electric light sources, e.g. electroluminescent light sources, and electrically or optically coupled thereto

Definitions

  • the present invention relates to a small reflective encoder that measures the displacement of a code wheel by a light receiving unit receiving reflected light from the code wheel as the code wheel moves.
  • Patent Document 1 Japanese Patent Application Laid-Open No. 08-250813 (hereinafter referred to as Patent Document 1) and Japanese Patent No. 4869641 (hereinafter referred to as Patent Document 2). ) are published and registered after each application.
  • the encoder described in Patent Document 1 converts the laser of the light source into circularly polarized light via a quarter-wave plate, and then transmits the displacement signal to the light receiving element by a code wheel that reflects incoherent light. Irradiation is a technical feature, and it is possible to maintain a stable output without being affected by return light. Further, the encoder described in Patent Document 2 has a technical feature that a part of outgoing light totally reflected in a package made of a light-transmitting resin is incident only on the outside of the light receiving unit, and is output from the light receiving unit. In addition to preventing signal saturation, the effect of optimizing the DC component of the output signal is obtained.
  • the above-described conventional invention has a problem that it is difficult to reduce the size while maintaining accuracy when further downsizing is required due to its structure.
  • the encoder described in Patent Document 1 is required to reduce both the pitch of the mirror used for the code wheel and the laser diameter on the outgoing light side due to its structure.
  • the pitch is narrowed to increase the resolution, the light irradiated to the light receiving unit is affected by the diffraction of the code wheel in addition to the waveform due to the reflection and transmission of the code wheel.
  • the pitch is miniaturized, the output amplitude of the structure described in Patent Document 1 is averaged and reduced, making it difficult to detect the rotational speed.
  • the invention described in the present application aims to provide a highly accurate reflective encoder that can be easily downsized with a simple configuration.
  • a first aspect of the present application is a reflection type encoder in which a reflection type diffraction grating is provided on a code wheel, and an interference optical system is sandwiched between the code wheel, a laser oscillator, and a light receiving unit.
  • the technical feature of the interference optical system is that a transmission diffraction grating having the same pitch as the diffraction grating is provided.
  • a reflective encoder in which a diffraction grating having a pitch of 10 ⁇ m or less is formed on a code wheel is used as its basic structure.
  • the resolution R [LPI of the encoder before the electrical multiplication processing is performed on the distance P [ ⁇ m] between the points in the plane parallel to the light receiving element in the optical path from the light source to the light receiving element.
  • the invention described in the present application is such that even if the diffraction grating pitch of the code wheel is narrowed, the signal from the reflective diffraction grating provided in the code wheel is reliably irradiated to the light receiving unit.
  • An encoder can be provided. This is because, in the reflective encoder, the interference optical system is sandwiched between the code wheel, the laser oscillator, and the light receiving unit, and the pitches of the diffraction gratings provided in the code wheel and the interference optical system are aligned. It has become an effect.
  • the reflective encoder described in the present application splits the reference light from the outgoing light emitted from the laser oscillator by sandwiching the interference optical system, and re-enters the interference optical system from the reflective diffraction grating. It makes it possible to interfere with light. For this reason, by aligning the pitches of the transmission diffraction grating and the reflection diffraction grating provided in the interference optical system, the angle of the re-incident light is aligned with that of the outgoing light, and the circuit generated when the pitch is narrowed. It is possible to deal with the spread of the corners.
  • the laser oscillator and the light receiving unit are integrated corresponding to the spread of the diffraction angle, and the interference light is irradiated to the light receiving unit, thereby reducing the size and pitch of the entire encoder including the optical path. It is possible to simultaneously improve the resolution of the encoder by narrowing.
  • the invention described in the present application can simplify the optical system of the encoder. This is due to the fact that the optical paths of the re-incident light and the outgoing light are set parallel to each other in the interference optical system. That is, in the encoder described in the present application, the projection area in the plane direction is determined by the final irradiation position of the re-incident light and the emission position of the emitted light. For this reason, by making the optical paths of the re-incident light and the outgoing light parallel, the incident angle from the interference optical system to the code wheel is set to be vertical, and the laser oscillator and the light receiving unit are parallel to the code wheel.
  • the optical system can be simplified by reducing the number of optical components to be used, and the projection area can be minimized.
  • it is possible to cope with further downsizing of various optical components such as the laser oscillator and the light receiving unit without changing the optical path.
  • the reflected light from the reflective diffraction grating can be used as two. More specifically, the optical path of the re-incident light is configured to be symmetrical with respect to the outgoing light, and two systems of outputs can be obtained from a single reflective diffraction grating. For this reason, by providing a phase difference between the two systems of re-incident light, it is possible to cause a difference in the light receiving unit signals of the two systems and easily detect the displacement direction.
  • the size and resolution of the entire encoder when the diffraction grating pitch on the code wheel is increased to 10 ⁇ m or less and the encoder is reduced in size are optimized.
  • a diffraction grating that forms a pitch of 10 ⁇ m or less is used, an optical system corresponding to a diffraction angle that expands with an increase in accuracy of the pitch is configured, and the distance between the light receiving element and the light source and the pitch.
  • the overall dimensions of the encoder are defined by the distance between the light receiving element and the light source. For this reason, the above-mentioned effect can be imparted to an encoder that is multi-channeled using the same code wheel as an encoder provided with a plurality of light receiving portions.
  • the light receiving section used in this embodiment is premised on the use of the same encoder, and the type of signal irradiated to the light receiving section is not limited.
  • an encoder that reliably irradiates the laser light transmitting part and the light receiving part mounted at a narrow pitch is provided. can do.
  • FIG. 1 the best embodiment of the present invention will be described with reference to FIGS. 1, 2, 3, 4, 5, 6, and 7.
  • FIG. In addition, about the symbol and component number in a figure, the common symbol or number is provided to what functions as the same component.
  • FIG. 1 is a transmission perspective view of a reflective encoder used in the present embodiment
  • FIG. 2 is a side view showing an optical path used in the encoder
  • FIG. 3 is a basic optical path
  • FIG. 4 is a side view showing the principle of the basic optical path.
  • 5 shows an optical path related to the monitor signal of the encoder
  • FIG. 6 shows an optical path related to the origin signal of the encoder
  • FIG. 7 shows a side view of the optical path shown in FIGS.
  • the code wheel 9 which functions as a rotary body
  • omitted is abbreviate
  • the interference optical system is transmitted from the code wheel.
  • the light re-incident light and the monitor signal reflected only in the interference optical system are irradiated to the light receiving portions 7a, 7b, 7c and 7d provided around the semiconductor laser.
  • the pitches of the reflective diffraction grating 4 and the transmissive diffraction gratings 3b and 3c used in this embodiment are both 10 ⁇ m or less.
  • an optical path distance P [ ⁇ m] between the semiconductor laser and each light receiving portion in the present embodiment is set between 5 and 30.
  • the reflection type diffraction grating 4 is formed in an annular shape, and only a part thereof is shown in the drawing.
  • the encoder described in the present embodiment has a component configuration using only the semiconductor laser 1 as a light source, but has a plurality of code wheel 9 displacements, movement amounts, rotation speeds, and operation signals of the oscillator. Signal output is possible.
  • the encoder described in the present embodiment has a component configuration using only the semiconductor laser 1 as a light source, but has a plurality of code wheel 9 displacements, movement amounts, rotation speeds, and operation signals of the oscillator. Signal output is possible.
  • the encoder described in the present embodiment has a component configuration using only the semiconductor laser 1 as a light source, but has a plurality of code wheel 9 displacements, movement amounts, rotation speeds, and operation signals of the oscillator. Signal output is possible.
  • the ratio and using it as a value for the resolution R of the encoder
  • the transmissive diffraction grating 3 a is used to divide the reference lights e ⁇ b> 1 and e ⁇ b> 2 from the emitted light of the semiconductor laser 1, and the emitted light is reflected to the reflective diffraction grating 4.
  • the reflection type diffraction grating 4 causes the two re-incident lights incident on the interference optical system 10 from the diffraction grating to interfere with the reference lights e1 and e2 in the interference optical system, and irradiates the light receiving parts 7a and 7b.
  • the displacement information of the reflective diffraction grating 4 can be acquired from each light receiving section.
  • the phase shifter 5 for one of the two re-incident lights, it is possible to shift the output waveform between the two light receiving portions and detect the displacement direction from the difference between the output signals. It has become possible.
  • this embodiment uses a configuration in which the pitches of the reflection type diffraction grating 4 and the transmission type diffraction gratings 3b and 3c provided in the interference optical system 10 are aligned. For this reason, the re-incident light and the outgoing light in the interference optical system used in the basic structure are made parallel to each other, the optical system of the encoder is simplified, and the semiconductor laser 1 and the light receiving portions 7a and 7b are coded. It could be installed parallel to the wheel 9.
  • the semiconductor laser 1 and the light receiving unit can be integrated with respect to the widening of the folding angle, and the encoder as a whole including the optical path can be miniaturized and the resolution of the encoder can be improved at the same pitch.
  • an optical path different from the reference light is divided in the interference optical system, and the light receiving unit 7c is irradiated using the reflector 6b. Yes. Therefore, the monitor signal for confirming the operation status of the semiconductor laser 1 can be outputted from the light receiving unit 7c in the structure which is miniaturized.
  • a structure in which incident light from the interference optical system 10 to the code wheel 9 is irradiated to the light receiving unit 7d via the reflector 6a. Used.
  • this optical path uses a configuration in which the distance P between the optical paths of the laser oscillator and each light receiving unit is aligned with the distance between the optical paths shown in FIG.
  • the encoder that reliably irradiates the laser light transmitting unit and the light receiving unit mounted at a narrow pitch can be provided.
  • the encoder that reliably irradiates the laser light transmitting unit and the light receiving unit mounted at a narrow pitch can be provided.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • Electromagnetism (AREA)
  • Engineering & Computer Science (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Power Engineering (AREA)
  • Optical Transform (AREA)
  • Light Receiving Elements (AREA)

Abstract

[Problem] To provide a reflective encoder with which a light receiving unit mounted at a narrow pitch from a laser light emitting unit can be reliably irradiated even when the diffraction grating pitch of a code wheel is narrowed. [Solution] Between a sub-mount to which a laser oscillator and a light receiving unit are attached and a code wheel provided with a reflective diffraction grating, there is sandwiched an interference optical system including a transmission diffraction grating having the same pitch as the reflective diffraction grating, whereby it becomes possible to reliably irradiate the light receiving unit with re-incident light returning via the code wheel.

Description

反射型エンコーダReflective encoder
　本発明は、コードホイールの移動に伴い、当該コードホイールからの反射光を受光部が受けてコードホイールの変位を測定する小形の反射型エンコーダに関する。 The present invention relates to a small reflective encoder that measures the displacement of a code wheel by a light receiving unit receiving reflected light from the code wheel as the code wheel moves.
　現在、産業用ロボット等に搭載されているステッピングモータ及びリニアアクチュエータには、高精度での位置決めを可能にするため、小形、高分解能のエンコーダが複数搭載されている。この様なエンコーダの中で、小型化が容易なものとして反射型エンコーダがあり、代表的な構造として特開平０８－２５０８１３（以下特許文献１として記載）及び特許４８６９６４１号（以下特許文献２として記載）がそれぞれ出願後、公開及び登録されている。 Currently, multiple stepping motors and linear actuators mounted on industrial robots are equipped with multiple small and high-resolution encoders in order to enable highly accurate positioning. Among such encoders, there is a reflective encoder that can be easily reduced in size. Representative structures include Japanese Patent Application Laid-Open No. 08-250813 (hereinafter referred to as Patent Document 1) and Japanese Patent No. 4869641 (hereinafter referred to as Patent Document 2). ) Are published and registered after each application.
　これら２件のうち、特許文献１記載のエンコーダは、１／４波長板を介して光源のレーザーを円偏光に変換した後、非干渉性の光を反射するコードホイールによって変位信号を受光素子に照射することをその技術的特徴としており、戻り光の影響を受けること無く安定した出力を維持することを可能にしている。また、特許文献２記載のエンコーダは、光透過性樹脂によるパッケージ内で全反射される出射光の一部を受光部外側のみに入射させることをその技術的特徴としており、受光部から出力される信号の飽和を防ぐと共に、出力信号のＤＣ成分の最適化という効果を得ている。 Of these two cases, the encoder described in Patent Document 1 converts the laser of the light source into circularly polarized light via a quarter-wave plate, and then transmits the displacement signal to the light receiving element by a code wheel that reflects incoherent light. Irradiation is a technical feature, and it is possible to maintain a stable output without being affected by return light. Further, the encoder described in Patent Document 2 has a technical feature that a part of outgoing light totally reflected in a package made of a light-transmitting resin is incident only on the outside of the light receiving unit, and is output from the light receiving unit. In addition to preventing signal saturation, the effect of optimizing the DC component of the output signal is obtained.
特開平０８－２５０８１３号公報Japanese Patent Laid-Open No. 08-250813 特許４８６９６４１号公報Japanese Patent No. 4869641
　上述した効果を有している一方で、上記従来の発明はその構造上、更なる小型化が要求された際に、精度を維持しつつ小型化することが難しいという課題を有していた。即ち、特許文献１記載のエンコーダはその構造上、小型化に際して、コードホイールに用いるミラーのピッチと出射光側のレーザー径とを共に小型化する必要がある。加えて、分解能を高めるためにピッチを狭めると、受光部に照射される光はコードホイールの反射及び透過による波形に加え、コードホイールの回折による影響を受ける。これにより、当該ピッチの微細化に際して、特許文献１記載の構造は出力振幅が平均化されて減少し、回転数の検出が困難になる。 While having the above-described effects, the above-described conventional invention has a problem that it is difficult to reduce the size while maintaining accuracy when further downsizing is required due to its structure. In other words, the encoder described in Patent Document 1 is required to reduce both the pitch of the mirror used for the code wheel and the laser diameter on the outgoing light side due to its structure. In addition, when the pitch is narrowed to increase the resolution, the light irradiated to the light receiving unit is affected by the diffraction of the code wheel in addition to the waveform due to the reflection and transmission of the code wheel. As a result, when the pitch is miniaturized, the output amplitude of the structure described in Patent Document 1 is averaged and reduced, making it difficult to detect the rotational speed.
また、特許文献２記載のエンコーダは干渉縞の明暗をアナログ値として取得する反面、出射光の一部を受光部に入射しなければならない。この為、分解能を高めるためにピッチを狭めた際には回折角が広くなり、発光素子と受光素子との距離を狭めることが難しい。 Further, while the encoder described in Patent Document 2 acquires the brightness of the interference fringes as an analog value, a part of the emitted light must be incident on the light receiving unit. For this reason, when the pitch is narrowed to increase the resolution, the diffraction angle becomes wide, and it is difficult to narrow the distance between the light emitting element and the light receiving element.
　上記課題に対して本願記載の発明では、簡単な構成により小型化が容易で、高精度な反射型エンコーダの提供を目的としている。
In order to solve the above-described problems, the invention described in the present application aims to provide a highly accurate reflective encoder that can be easily downsized with a simple configuration.
　上記目的のために本願に於ける第１の態様は、コードホイールに反射型回折格子を設け、当該コードホイールと、レーザー発振器及び受光部と、の間に干渉光学系を挟んだ反射型エンコーダを基本構造として用いている。また、当該干渉光学系に前記回折格子と同ピッチの透過型回折格子を設けたことをその技術的特徴としている。 For the above purpose, a first aspect of the present application is a reflection type encoder in which a reflection type diffraction grating is provided on a code wheel, and an interference optical system is sandwiched between the code wheel, a laser oscillator, and a light receiving unit. Used as a basic structure. The technical feature of the interference optical system is that a transmission diffraction grating having the same pitch as the diffraction grating is provided.
　更に、本願に於ける第２の態様では、コードホイール上にピッチ１０μｍ以下の回折格子が形成された反射型エンコーダをその基本構造として用いている。加えて、光源から受光素子までの光路のうち、受光素子と平行な面内に於ける距離が最も遠い地点同士の距離Ｐ［μｍ］に対する電気的逓倍処理を施す前のエンコーダの分解能Ｒ［ＬＰＩ］の比率Ｆ（＝Ｒ／Ｐ）が５乃至３０の範囲としたことをその技術的特徴としている。
Furthermore, in the second aspect of the present application, a reflective encoder in which a diffraction grating having a pitch of 10 μm or less is formed on a code wheel is used as its basic structure. In addition, the resolution R [LPI of the encoder before the electrical multiplication processing is performed on the distance P [μm] between the points in the plane parallel to the light receiving element in the optical path from the light source to the light receiving element. The ratio F (= R / P) in the range of 5 to 30 is a technical feature.
　上述した技術的特徴によって本願記載の発明は、前記コードホイールの回折格子ピッチが狭くなっても、当該コードホイールに設けられた反射型回折格子からの信号が前記受光部に対して確実に照射されるエンコーダを提供することができる。これは、反射型エンコーダに於いて、コードホイールと、レーザー発振器及び受光部と、の間に干渉光学系を挟み、当該コードホイールと干渉光学系とに設けた回折格子のピッチを揃えた事による効果となっている。即ち、本願記載の反射型エンコーダは、前記干渉光学系を挟むことでレーザー発振器から出射された出射光から参照光を分割し、前記反射型回折格子から当該干渉光学系内へ入射される再入射光と干渉させることを可能にしている。この為、当該干渉光学系に設けた透過型回折格子と前記反射型回折格子とのピッチを揃えることで、前記再入射光の角度を前記出射光と揃え、前記ピッチを狭めた際に生じる回折角の広がりに対応することができる。また、当該回折角の広がりに対応して、前記レーザー発振器と受光部とを集積し、前記干渉させた光を受光部へと照射させることで、光路も含めたエンコーダ全体の小型化とピッチを狭めることによるエンコーダの分解能向上とを同時に行うことが可能となる。 Due to the technical features described above, the invention described in the present application is such that even if the diffraction grating pitch of the code wheel is narrowed, the signal from the reflective diffraction grating provided in the code wheel is reliably irradiated to the light receiving unit. An encoder can be provided. This is because, in the reflective encoder, the interference optical system is sandwiched between the code wheel, the laser oscillator, and the light receiving unit, and the pitches of the diffraction gratings provided in the code wheel and the interference optical system are aligned. It has become an effect. That is, the reflective encoder described in the present application splits the reference light from the outgoing light emitted from the laser oscillator by sandwiching the interference optical system, and re-enters the interference optical system from the reflective diffraction grating. It makes it possible to interfere with light. For this reason, by aligning the pitches of the transmission diffraction grating and the reflection diffraction grating provided in the interference optical system, the angle of the re-incident light is aligned with that of the outgoing light, and the circuit generated when the pitch is narrowed. It is possible to deal with the spread of the corners. In addition, the laser oscillator and the light receiving unit are integrated corresponding to the spread of the diffraction angle, and the interference light is irradiated to the light receiving unit, thereby reducing the size and pitch of the entire encoder including the optical path. It is possible to simultaneously improve the resolution of the encoder by narrowing.
　また、上記構成とすることによって本願記載の発明は、エンコーダの光学系を簡素化する事ができる。これは、前記干渉光学系内に於いて、再入射光と出射光の光路を互いに平行な状態に設定したことによる効果となっている。即ち、本願記載のエンコーダに於いて、平面方向の投影面積は、前記再入射光の最終的な照射位置と出射光の出射位置とによって決定される。この為、前記再入射光と出射光の光路を平行にすることで、前記干渉光学系からコードホイールへの入射角を垂直に設定し、レーザー発振器と受光部とをコードホイールに対して平行に設置できると共に、使用する光学部品の点数を抑えて光学系を簡素化し、前記投影面積を最小にすることが可能となる。加えて、当該効果の付与によって、前記レーザー発振器と受光部等、各種光学部品の更なる小型化に際しても、光路を変更することなく対応することができる。 In addition, with the above-described configuration, the invention described in the present application can simplify the optical system of the encoder. This is due to the fact that the optical paths of the re-incident light and the outgoing light are set parallel to each other in the interference optical system. That is, in the encoder described in the present application, the projection area in the plane direction is determined by the final irradiation position of the re-incident light and the emission position of the emitted light. For this reason, by making the optical paths of the re-incident light and the outgoing light parallel, the incident angle from the interference optical system to the code wheel is set to be vertical, and the laser oscillator and the light receiving unit are parallel to the code wheel. In addition to being able to be installed, the optical system can be simplified by reducing the number of optical components to be used, and the projection area can be minimized. In addition, by applying the effect, it is possible to cope with further downsizing of various optical components such as the laser oscillator and the light receiving unit without changing the optical path.
　更に、本願記載の発明では、前記再入射光と出射光の光路を互いに平行な状態に設定したことで、反射型回折格子からの反射光を２本として使用することができる。より具体的には、前記再入射光の光路を出射光に対して対称形状に構成し、単一の前記反射型回折格子から２系統の出力を得ることが可能となる。この為、前記２系統の再入射光に位相差を設けることで当該２系統の各受光部信号に差異を生じさせ、変位方向の検出を容易に行うことができる。 Furthermore, in the invention described in the present application, by setting the optical paths of the re-incident light and the outgoing light in parallel with each other, the reflected light from the reflective diffraction grating can be used as two. More specifically, the optical path of the re-incident light is configured to be symmetrical with respect to the outgoing light, and two systems of outputs can be obtained from a single reflective diffraction grating. For this reason, by providing a phase difference between the two systems of re-incident light, it is possible to cause a difference in the light receiving unit signals of the two systems and easily detect the displacement direction.
　また、本願第２の態様を用いることで、前記小型化されていくエンコーダについて、コードホイール上の回折格子ピッチを１０μｍ以下として高精度化した場合のエンコーダ全体の寸法と分解能とを最適な値に保つことができる。より具体的には、１０μｍ以下のピッチを形成する回折格子の使用に際して、当該ピッチの高精度化に伴い拡大する回折角に対応した光学系を構成し、受光素子－光源間の距離と当該ピッチに起因する分解能を規定することで、エンコーダの小型化と分解能の向上とを両立することができる。加えて、使用する光源の波長と同程度となる１０μｍ以下のピッチを形成する回折格子の微細加工に対して、当該微細加工による効果を最大限発揮させることが可能となっている。 In addition, by using the second aspect of the present application, the size and resolution of the entire encoder when the diffraction grating pitch on the code wheel is increased to 10 μm or less and the encoder is reduced in size are optimized. Can keep. More specifically, when a diffraction grating that forms a pitch of 10 μm or less is used, an optical system corresponding to a diffraction angle that expands with an increase in accuracy of the pitch is configured, and the distance between the light receiving element and the light source and the pitch By defining the resolution resulting from the above, it is possible to achieve both the miniaturization of the encoder and the improvement of the resolution. In addition, it is possible to maximize the effects of the fine processing with respect to the fine processing of the diffraction grating that forms a pitch of 10 μm or less, which is the same as the wavelength of the light source to be used.
　更に、本態様では、受光素子－光源間の距離によって前記エンコーダ全体の寸法を規定している。この為、同一のコードホイールを用いて多チャンネル化されたエンコーダに対しても、複数の受光部を設けたエンコーダとして前記効果を付与することができる。尚、本態様に於いて用いる受光部は同一のエンコーダで用いることを前提としており、受光部が照射される信号の種類については制限されない。 Furthermore, in this embodiment, the overall dimensions of the encoder are defined by the distance between the light receiving element and the light source. For this reason, the above-mentioned effect can be imparted to an encoder that is multi-channeled using the same code wheel as an encoder provided with a plurality of light receiving portions. Note that the light receiving section used in this embodiment is premised on the use of the same encoder, and the type of signal irradiated to the light receiving section is not limited.
　以上述べたように、本願請求項記載の構造を用いることによってコードホイールの回折格子ピッチが狭くなっても、レーザー光発信部と狭ピッチに実装された受光部に確実に照射されるエンコーダを提供することができる。
As described above, even when the diffraction grating pitch of the code wheel is narrowed by using the structure described in the claims of the present application, an encoder that reliably irradiates the laser light transmitting part and the light receiving part mounted at a narrow pitch is provided. can do.
本発明の実施形態に於いて用いる反射型エンコーダの透過斜視図Transmission perspective view of a reflective encoder used in an embodiment of the present invention 図１に於いて示した反射型エンコーダの光路を示す説明図Explanatory drawing which shows the optical path of the reflection type encoder shown in FIG. 図１に於いて示した反射型エンコーダの基本光路を示す説明図Explanatory drawing which shows the basic optical path of the reflection type encoder shown in FIG. 図１に於いて示した反射型エンコーダの基本原理を示す側面図Side view showing the basic principle of the reflective encoder shown in FIG. 図１に於いて示した反射型エンコーダのモニタ信号に関わる光路を示す説明図Explanatory drawing which shows the optical path in connection with the monitor signal of the reflection type encoder shown in FIG. 図１に於いて示した反射型エンコーダの原点信号に関わる光路を示す説明図Explanatory drawing which shows the optical path in connection with the origin signal of the reflective encoder shown in FIG. 図５及び図６に於いて示した各信号の原理を示す側面図Side view showing the principle of each signal shown in FIG. 5 and FIG.
　以下に、図１、図２、図３、図４、図５、図６及び図７を用いて、本発明に於ける最良の実施形態を示す。尚、図中の記号及び部品番号について、同じ部品として機能するものには共通の記号又は番号を付与している。 Hereinafter, the best embodiment of the present invention will be described with reference to FIGS. 1, 2, 3, 4, 5, 6, and 7. FIG. In addition, about the symbol and component number in a figure, the common symbol or number is provided to what functions as the same component.
　図１に本実施形態に於いて用いる反射型エンコーダの透過斜視図を、図２に同エンコーダで使用する光路を、図３に同基本光路を、図４に同基本光路の原理を示す側面図を、図５に同エンコーダのモニタ信号に関わる光路を、図６に同エンコーダの原点信号に関わる光路を、そして図７に図５及び図６に於いて示した光路の側面図をそれぞれ示す。尚、各素子の回路、回転体として機能するコードホイール９、エンコーダ全体の支持構造及び、コードホイール上に設けた反射型回折格子４の全体については、図中での記載を省略している。 FIG. 1 is a transmission perspective view of a reflective encoder used in the present embodiment, FIG. 2 is a side view showing an optical path used in the encoder, FIG. 3 is a basic optical path, and FIG. 4 is a side view showing the principle of the basic optical path. 5 shows an optical path related to the monitor signal of the encoder, FIG. 6 shows an optical path related to the origin signal of the encoder, and FIG. 7 shows a side view of the optical path shown in FIGS. In addition, about the circuit of each element, the code wheel 9 which functions as a rotary body, the support structure of the whole encoder, and the whole reflection type diffraction grating 4 provided on the code wheel, description in a figure is abbreviate | omitted.
　図１及び図２から解るように、本実施形態ではレーザー発振器となる半導体レーザー１から出射された出射光を干渉光学系１０を介してコードホイール９へと入射させ、当該コードホイールから干渉光学系への再入射光及び干渉光学系内のみで反射させたモニタ信号を半導体レーザーの周囲に設けた受光部７ａ、７ｂ、７ｃ及び７ｄへと照射している。ここで、本実施形態にて用いる反射型回折格子４及び透過型回折格子３ｂ、３ｃのピッチは共に１０μｍ以下となっている。また、半導体レーザー１に対して等距離に配置された各受光部７ａ、７ｂ、７ｃ及び７ｄについて、本実施形態に於ける半導体レーザーと各受光部との間の光路間距離Ｐ［μｍ］とエンコーダの分解能Ｒ［ＬＰＩ］との比率Ｆ（＝Ｒ／Ｐ）は５～３０の間に設定されている。尚、反射型回折格子４は円環状に形成されており、図中ではその一部のみを記載している。 As can be seen from FIGS. 1 and 2, in this embodiment, light emitted from the semiconductor laser 1 serving as a laser oscillator is incident on the code wheel 9 via the interference optical system 10, and the interference optical system is transmitted from the code wheel. The light re-incident light and the monitor signal reflected only in the interference optical system are irradiated to the light receiving portions 7a, 7b, 7c and 7d provided around the semiconductor laser. Here, the pitches of the reflective diffraction grating 4 and the transmissive diffraction gratings 3b and 3c used in this embodiment are both 10 μm or less. In addition, for each of the light receiving portions 7a, 7b, 7c, and 7d arranged at an equal distance from the semiconductor laser 1, an optical path distance P [μm] between the semiconductor laser and each light receiving portion in the present embodiment The ratio F (= R / P) to the encoder resolution R [LPI] is set between 5 and 30. Incidentally, the reflection type diffraction grating 4 is formed in an annular shape, and only a part thereof is shown in the drawing.
　この様な構造を用いたことで本実施形態記載のエンコーダは、半導体レーザー１のみを光源とした部品構成でありながら、コードホイール９の変位、移動量、回転数及び当該発振器の動作信号といった複数の信号出力を可能としている。また、前記比率の設定によって底部を構成するレーザー発振器及び受光部の平面配置を規定し、エンコーダの分解能Ｒに対する値として用いたことで、小型化と分解能の向上とを両立したエンコーダを得ることができた。 By using such a structure, the encoder described in the present embodiment has a component configuration using only the semiconductor laser 1 as a light source, but has a plurality of code wheel 9 displacements, movement amounts, rotation speeds, and operation signals of the oscillator. Signal output is possible. In addition, by defining the plane arrangement of the laser oscillator and the light receiving portion constituting the bottom by setting the ratio and using it as a value for the resolution R of the encoder, it is possible to obtain an encoder that achieves both miniaturization and improvement in resolution. did it.
　また、図３及び図４から解るように、本実施形態では透過型回折格子３ａを用いて半導体レーザー１の出射光から参照光ｅ１、ｅ２を分割し、当該出射光を反射型回折格子４へと入射させている。反射型回折格子４は、当該回折格子から干渉光学系１０へ入射する２本の再入射光と前記各参照光ｅ１、ｅ２とを干渉光学系内にて干渉させ、受光部７ａ、７ｂに照射させることで、各受光部から反射型回折格子４の変位情報を取得することができる。また、前記２本の再入射光のうち一方に位相シフタ５を用いたことで、前記２つの受光部間に於ける出力波形をずらし、当該出力信号間の差異から変位方向を検出することが可能となった。 As can be seen from FIGS. 3 and 4, in this embodiment, the transmissive diffraction grating 3 a is used to divide the reference lights e <b> 1 and e <b> 2 from the emitted light of the semiconductor laser 1, and the emitted light is reflected to the reflective diffraction grating 4. Is incident. The reflection type diffraction grating 4 causes the two re-incident lights incident on the interference optical system 10 from the diffraction grating to interfere with the reference lights e1 and e2 in the interference optical system, and irradiates the light receiving parts 7a and 7b. By doing so, the displacement information of the reflective diffraction grating 4 can be acquired from each light receiving section. Further, by using the phase shifter 5 for one of the two re-incident lights, it is possible to shift the output waveform between the two light receiving portions and detect the displacement direction from the difference between the output signals. It has become possible.
　上述した基本構造に於いて、本実施形態では反射型回折格子４と干渉光学系１０に設けた透過型回折格子３ｂ及び３ｃのピッチを揃えた構成を用いている。この為、当該基本構造に於いて用いる干渉光学系内の再入射光と出射光とを互いに平行な状態とし、エンコーダの光学系を簡素化すると共に、半導体レーザー１と受光部７ａ、７ｂをコードホイール９に対して平行に設置することができた。また、前記ピッチによって受光部７ａ、７ｂへの照射角を垂直としたことで、当該受光部への照射を確実に行うことができると共に、加工精度の向上に伴いピッチを狭めた際に生じる回折角の広がりに対して、半導体レーザー１と受光部との集積化を可能とし、光路も含めたエンコーダ全体の小型化と当該ピッチによるエンコーダの分解能向上とを同時に行うことができた。 In the basic structure described above, this embodiment uses a configuration in which the pitches of the reflection type diffraction grating 4 and the transmission type diffraction gratings 3b and 3c provided in the interference optical system 10 are aligned. For this reason, the re-incident light and the outgoing light in the interference optical system used in the basic structure are made parallel to each other, the optical system of the encoder is simplified, and the semiconductor laser 1 and the light receiving portions 7a and 7b are coded. It could be installed parallel to the wheel 9. In addition, by making the irradiation angle to the light receiving portions 7a and 7b vertical by the pitch, irradiation to the light receiving portions can be surely performed, and the rotation that occurs when the pitch is narrowed as the processing accuracy is improved. The semiconductor laser 1 and the light receiving unit can be integrated with respect to the widening of the folding angle, and the encoder as a whole including the optical path can be miniaturized and the resolution of the encoder can be improved at the same pitch.
　上述した効果に加えて、図５に示すように、本実施形態では干渉光学系内にて前記参照光とは別の光路を分割し、反射体６ｂを用いて受光部７ｃへと照射している。この為、前記小型化されていく構造に於いて、半導体レーザー１の動作状況を確認するモニタ信号を受光部７ｃから出力させることができた。また、図６に示すように、本実施形態では前記再入射光とは別に、干渉光学系１０からコードホイール９への入射光について、反射体６ａを介して受光部７ｄへと照射する構造を用いている。この為、当該信号の有無を原点信号としてコードホイール９の回転数を取得し、上述した各信号と併せてエンコーダの動作を検出することができる。尚、図７に示すように、本光路ではレーザー発振器－各受光部の光路間距離Ｐを、図２に示した光路間距離と揃えた構成を用いている。 In addition to the effects described above, as shown in FIG. 5, in this embodiment, an optical path different from the reference light is divided in the interference optical system, and the light receiving unit 7c is irradiated using the reflector 6b. Yes. Therefore, the monitor signal for confirming the operation status of the semiconductor laser 1 can be outputted from the light receiving unit 7c in the structure which is miniaturized. In addition, as shown in FIG. 6, in the present embodiment, apart from the re-incident light, a structure in which incident light from the interference optical system 10 to the code wheel 9 is irradiated to the light receiving unit 7d via the reflector 6a. Used. For this reason, the number of rotations of the code wheel 9 can be acquired using the presence / absence of the signal as an origin signal, and the operation of the encoder can be detected together with the above-described signals. As shown in FIG. 7, this optical path uses a configuration in which the distance P between the optical paths of the laser oscillator and each light receiving unit is aligned with the distance between the optical paths shown in FIG.
　また、本実施形態では半導体レーザー１及び各受光部７ａ、７ｂ、７ｃ及び７ｄを共通のサブマウント８に設けた構造を用いている。この為、前記小型化に伴い要求される干渉光学系との位置決めに関して、サブマウント上での位置決めを高精度で行った後、サブマウント８－干渉光学系１０間の調整により一括して行うことが可能となっている。 In this embodiment, a structure in which the semiconductor laser 1 and the light receiving portions 7a, 7b, 7c, and 7d are provided on the common submount 8 is used. For this reason, the positioning with the interference optical system required in accordance with the downsizing is performed in a lump by adjusting the position between the submount 8 and the interference optical system 10 after positioning on the submount with high accuracy. Is possible.
　以上述べたように、本願実施形態記載の構造を用いることによって、コードホイールの回折格子ピッチが狭くなっても、レーザー光発信部と狭ピッチに実装された受光部に確実に照射されるエンコーダを提供することができた。
As described above, by using the structure described in the embodiment of the present application, even when the diffraction grating pitch of the code wheel is narrowed, the encoder that reliably irradiates the laser light transmitting unit and the light receiving unit mounted at a narrow pitch can be provided. Could be provided.
　１　　　　　　　　　　　半導体レーザー
　２　　　　　　　　　　　レンズ
　３ａ、３ｂ、３ｃ　　　　透過型回折格子
　４　　　　　　　　　　　反射型回折格子
　５　　　　　　　　　　　位相シフタ
　６ａ、６ｂ、６ｃ、６ｄ　反射体
　７ａ、７ｂ、７ｃ、７ｄ　受光部
　８　　　　　　　　　　　サブマウント
　９　　　　　　　　　　　コードホイール
１０　　　　　　　　　　　干渉光学系
１１　　　　　　　　　　　基板
１２　　　　　　　　　　　スペーサ
　ｅ１、ｅ２　　　　　　　参照光 DESCRIPTION OF SYMBOLS 1 Semiconductor laser 2 Lens 3a, 3b, 3c Transmission type diffraction grating 4 Reflection type diffraction grating 5 Phase shifter 6a, 6b, 6c, 6d Reflector 7a, 7b, 7c, 7d Light-receiving part 8 Submount 9 Code wheel 10 Interference optical system 11 Substrate 12 Spacer e1, e2 Reference light

Claims (2)

  1. 平行移動可能な回折格子と、当該回折格子と対向配置したレーザー発振器及び受光部と、の間に干渉光学系を挟んだ反射型エンコーダであって、
    当該干渉光学系が、前記回折格子と同ピッチの透過型回折格子を有している反射型エンコーダ。
    A reflective encoder having an interference optical system sandwiched between a parallel movable diffraction grating, and a laser oscillator and a light receiving unit disposed opposite to the diffraction grating,
    A reflective encoder in which the interference optical system has a transmissive diffraction grating having the same pitch as the diffraction grating.
  2. コードホイール上にピッチ１０μｍ以下の回折格子が形成された反射型エンコーダであって、
    光源から受光素子までの光路のうち、受光素子と平行な面内に於ける距離が最も遠い地点同士の距離Ｐ［μｍ］に対する電気的逓倍処理を施す前のエンコーダの分解能Ｒ［ＬＰＩ］の比率Ｆ（＝Ｒ／Ｐ）が５乃至３０の範囲にある反射型エンコーダ。     A reflective encoder in which a diffraction grating having a pitch of 10 μm or less is formed on a code wheel,
    Ratio of resolution R [LPI] of the encoder before performing electrical multiplication with respect to the distance P [μm] between points in the plane parallel to the light receiving element in the optical path from the light source to the light receiving element A reflective encoder having F (= R / P) in the range of 5 to 30.
PCT/JP2016/062299 2015-04-21 2016-04-19 Reflective encoder WO2016171108A1 (en)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH03279812A (en) * 1990-03-29 1991-12-11 Nikon Corp Diffraction interference type encoder
JP2008039487A (en) * 2006-08-02 2008-02-21 Canon Inc Manufacturing method of laminated structure, and manufacturing apparatus of the same
JP2013224936A (en) * 2012-04-20 2013-10-31 Mitsutoyo Corp Multiple wavelength configuration for optical encoder read head
JP2014535061A (en) * 2011-11-09 2014-12-25 ザイゴ コーポレーションＺｙｇｏ Ｃｏｒｐｏｒａｔｉｏｎ Small encoder head for interferometric encoder systems

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH03279812A (en) * 1990-03-29 1991-12-11 Nikon Corp Diffraction interference type encoder
JP2008039487A (en) * 2006-08-02 2008-02-21 Canon Inc Manufacturing method of laminated structure, and manufacturing apparatus of the same
JP2014535061A (en) * 2011-11-09 2014-12-25 ザイゴ コーポレーションＺｙｇｏ Ｃｏｒｐｏｒａｔｉｏｎ Small encoder head for interferometric encoder systems
JP2013224936A (en) * 2012-04-20 2013-10-31 Mitsutoyo Corp Multiple wavelength configuration for optical encoder read head

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