TWI830571B - Absolute encoder - Google Patents

Absolute encoder Download PDF

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Publication number
TWI830571B
TWI830571B TW112100393A TW112100393A TWI830571B TW I830571 B TWI830571 B TW I830571B TW 112100393 A TW112100393 A TW 112100393A TW 112100393 A TW112100393 A TW 112100393A TW I830571 B TWI830571 B TW I830571B
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absolute
light
absolute position
image sensor
scale
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TW112100393A
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TW202318811A (en
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北山泰広
樋口昭彦
目片敏男
大熊雅史
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日商三菱電機股份有限公司
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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
    • G01D5/34776—Absolute encoders with analogue or digital 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
    • G01D5/347—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
    • G01D5/347—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
    • 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

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optical Transform (AREA)
  • Transmission And Conversion Of Sensor Element Output (AREA)
  • Analogue/Digital Conversion (AREA)

Abstract

An absolute encoder (1X) calculates a first absolute position on a scale (20) based on light form a first position and light from a second position of the scale (20) arranged with an absolute value code pattern. The absolute value code pattern is formed of linear reflective parts and linear non-reflective parts that extend in a radial direction and are provided alternately in a circumferential direction on a surface of a disc-shaped scale at a side opposite to a light-emitting element, wherein the linear reflecting part and the linear non-reflecting part have a line width at the first position narrower than a line width at the second position, and the number of the reflective parts included at the first position is smaller than the number of the reflective parts included at the second position.

Description

絕對編碼器absolute encoder

本揭示係關於對測定對象物的角度位置進行測定之絕對編碼器。The present disclosure relates to an absolute encoder for measuring the angular position of a measurement object.

測定轉軸(shaft)等之測定對象物的機械的角度位置之絕對編碼器，係具備有：排列有複數個標記(mark)之圓板標度尺(scale)；以及藉由照射光到圓板標度尺來從圓板標度尺取得與測定對象物的角度位置對應的訊號之光感測器模組。An absolute encoder that measures the angular position of a measuring object such as a shaft, etc., has a circular plate scale with a plurality of marks arranged in it, and a circular plate that irradiates light. The optical sensor module uses the scale to obtain the signal corresponding to the angular position of the measurement object from the circular plate scale.

專利文獻1中揭示的絕對編碼器，係在圓板標度尺排列有由ABS　(ABSolute，絕對型的)圖案、INC(INCremental，增量型的)圖案所組合而成的標記。此絕對編碼器係利用兩個檢測器來取得從圓板標度尺取得的位置資訊，並將之分解成ABS圖案的位置資訊及INC圖案的位置資訊，再求出該兩種位置資訊的平均值，以此方式來提高位置資訊的解析度。 [先前技術文獻] [專利文獻] The absolute encoder disclosed in Patent Document 1 has a circular scale on which marks composed of an ABS (Absolute) pattern and an INC (INCremental) pattern are arranged. This absolute encoder uses two detectors to obtain the position information obtained from the circular plate scale, decomposes it into the position information of the ABS pattern and the position information of the INC pattern, and then calculates the average of the two position information. value to improve the resolution of location information. [Prior technical literature] [Patent Document]

[專利文獻1] 日本特許第5787513號公報[Patent Document 1] Japanese Patent No. 5787513

[發明所欲解決之課題][Problem to be solved by the invention]

然而，在上述專利文獻1之技術中，從圓板標度尺接收的光係從圓板標度尺的一個區域接收者，根據從一個區域接收的光而算出ABS圖案的位置資訊及INC圖案的位置資訊再求出平均值。因此，上述專利文獻1之技術，若兩個檢測器的任一個有異物附著等就會有損及位置資訊的可靠性之問題。However, in the technology of Patent Document 1 mentioned above, the light received from the disc scale is received from one area of the disc scale, and the position information of the ABS pattern and the INC pattern are calculated based on the light received from one area. The location information is then averaged. Therefore, the technology of the above-mentioned Patent Document 1 has a problem of damaging the reliability of the position information if foreign matter adheres to either of the two detectors.

本揭示係有鑑於上述課題而完成者，目的在於得到可算出可靠性高且解析度高的位置資料之絕對編碼器。 [解決課題之手段] This disclosure was made in view of the above-mentioned problems, and aims to obtain an absolute encoder that can calculate position data with high reliability and high resolution. [Means to solve the problem]

為了解決上述的課題，達成上述目的，本發明之絕對編碼器係具備有：配置有絕對值碼圖案之圓板狀的標度尺(scale)；以及照射光至標度尺之發光元件。而且，本揭示之絕對編碼器係具備有：接收來自與標度尺的中心相距第一距離的第一位置之第一光而輸出與第一光對應的第一類比訊號之第一影像感測器(image sensor)；以及接收來自與標度尺的中心相距第二距離的第二位置之第二光而輸出與第二光對應的第二類比訊號之第二影像感測器。而且，本發明之絕對編碼器係具備有：將第一類比訊號轉換為第一數位訊號之第一訊號轉換部；將第二類比訊號轉換為第二數位訊號之第二訊號轉換部；以及根據第一數位訊號及第二數位訊號而算出在標度尺上的第一絕對位置之絕對位置演算部。絕對值碼圖案係由在圓板狀的標度尺之與發光元件相對向之側的面內朝向徑向延伸且於周方向交錯設置的線狀的反射部及線狀的非反射部所形成，反射部及非反射部在第一位置的線寬比在第二位置的線寬窄，且在第一位置包含的反射部的條數比在第二位置包含的反射部的條數多。 [發明的效果] In order to solve the above-mentioned problems and achieve the above-mentioned objects, an absolute encoder of the present invention includes: a disc-shaped scale on which an absolute value code pattern is arranged; and a light-emitting element that irradiates light to the scale. Moreover, the absolute encoder of the present disclosure is provided with: a first image sensor that receives a first light from a first position that is a first distance away from the center of the scale and outputs a first analog signal corresponding to the first light. an image sensor; and a second image sensor that receives second light from a second position that is a second distance away from the center of the scale and outputs a second analog signal corresponding to the second light. Moreover, the absolute encoder of the present invention is provided with: a first signal conversion part that converts the first analog signal into a first digital signal; a second signal conversion part that converts the second analog signal into a second digital signal; and according to The absolute position calculation unit calculates the first absolute position on the scale based on the first digital signal and the second digital signal. The absolute value code pattern is formed by linear reflective portions and linear non-reflective portions extending in the radial direction and staggered in the circumferential direction in the surface of the disk-shaped scale on the side opposite to the light-emitting element. , the line width of the reflective part and the non-reflective part at the first position is narrower than the line width at the second position, and the number of reflective parts included in the first position is greater than the number of reflective parts included in the second position. [Effects of the invention]

本發明之絕對編碼器會產生可算出可靠性高且解析度高的位置資料之效果。The absolute encoder of the present invention has the effect of calculating position data with high reliability and high resolution.

以下，根據圖式來詳細說明本發明的實施型態之絕對編碼器。Hereinafter, the absolute encoder according to the embodiment of the present invention will be described in detail based on the drawings.

實施型態1. 圖1係顯示實施型態1之絕對編碼器的構成之圖。絕對編碼器1X係具備有發光元件2、影像感測器3X、4X、標度尺20、AD (類比至數位)轉換器5A、5B、及絕對位置演算部6X。 Implementation type 1. FIG. 1 is a diagram showing the structure of an absolute encoder according to Embodiment 1. The absolute encoder 1X is equipped with a light-emitting element 2, image sensors 3X, 4X, a scale 20, AD (analog to digital) converters 5A, 5B, and an absolute position calculation unit 6X.

發光元件2係照射光至標度尺20之照明部。發光元件2係採用例如點光源LED(Light Emitting Diode:發光二極體)。影像感測器3X、4X係接收來自標度尺20的光之光檢測部。影像感測器3X、4X係採用CCD(Charge Coupled Device:電荷耦合元件)影像感測器、CMOS(Complementary Metal Oxide Semiconductor:互補金屬氧化物膜半導體)影像感測器等之攝像裝置。實施型態1雖然是針對影像感測器3X、4X為一維的影像感測器之情況進行說明，但影像感測器3X、4X亦可為二維的影像感測器。The light-emitting element 2 irradiates light to the illumination part of the scale 20 . The light-emitting element 2 uses, for example, a point light source LED (Light Emitting Diode: Light Emitting Diode). The image sensors 3X and 4X receive light detection portions from the scale 20 . Image sensors 3X and 4X are camera devices that use CCD (Charge Coupled Device: Charge Coupled Device) image sensors, CMOS (Complementary Metal Oxide Semiconductor: Complementary Metal Oxide Film Semiconductor) image sensors, etc. Although Embodiment 1 is described with respect to the case where the image sensors 3X and 4X are one-dimensional image sensors, the image sensors 3X and 4X may also be two-dimensional image sensors.

標度尺20係圓板狀的標度尺。標度尺20係連結至馬達(未圖示)等所具備的旋轉軸7，而藉由旋轉軸7旋轉來使標度尺20旋轉。標度尺20在沿著圓周的方向設有一道軌跡(track)，該軌跡具有屬於絕對位置圖案之絕對值碼圖案30。在絕對值碼圖案30，配置有朝向標度尺20的徑向延伸之複數個反射部31及複數個非反射部32。The scale 20 is a circular plate-shaped scale. The scale 20 is connected to a rotation shaft 7 provided in a motor (not shown), etc., and the scale 20 is rotated by the rotation of the rotation shaft 7 . The scale 20 is provided with a track along the circumferential direction, and the track has an absolute value code pattern 30 belonging to the absolute position pattern. The absolute value code pattern 30 is provided with a plurality of reflective portions 31 and a plurality of non-reflective portions 32 extending in the radial direction of the scale 20 .

反射部31係會反射來自發光元件2的光的部分，非反射部32係會吸收來自發光元件2的光或讓來自發光元件2的光透射過的部分。非反射部32為以比反射部31的反射率低的反射率來進行反射的部分即可。反射部31及非反射部32以對於投影到影像感測器3X、4X上的光強度分布進行調變之方式發揮功能。The reflective part 31 is a part that reflects the light from the light-emitting element 2 , and the non-reflective part 32 is a part that absorbs the light from the light-emitting element 2 or transmits the light from the light-emitting element 2 . The non-reflective part 32 only needs to be a part that reflects with a lower reflectance than the reflectance of the reflective part 31 . The reflective part 31 and the non-reflective part 32 function to modulate the light intensity distribution projected onto the image sensors 3X and 4X.

絕對值碼圖案30係以對標度尺20的角度位置附加特徵之方式由反射部31及非反射部32構成。絕對值碼圖案30的排列係採用例如將M序列(M sequence)等之虛擬隨機碼(pseudo random codes)予以曼徹斯特編碼(Manchester coding)而得的碼列。The absolute value code pattern 30 is composed of a reflective part 31 and a non-reflective part 32 so as to add characteristics to the angular position of the scale 20 . The absolute value code pattern 30 is arranged using a code sequence obtained by subjecting pseudo random codes such as an M sequence to Manchester coding.

實施型態1揭示的例子，係發光元件2及影像感測器3X、4X都配置在標度尺20的單側的面之上表面之反射型編碼器。實施型態1之絕對編碼器1X亦可採用將發光元件2與影像感測器3X、4X配置在隔著標度尺20而相對向的位置之上表面及下表面之透射型編碼器。The example disclosed in Embodiment 1 is a reflective encoder in which the light-emitting element 2 and the image sensors 3X and 4X are arranged on the upper surface of one side of the scale 20 . The absolute encoder 1X of Embodiment 1 may also be a transmission-type encoder in which the light-emitting element 2 and the image sensors 3X and 4X are arranged on the upper and lower surfaces at opposite positions across the scale 20 .

透射型編碼器之情況，絕對值碼圖案30可由光會透射過的透射部及光不會透射過的非透射部所構成。不論是在反射型編碼器還是透射型編碼器的情況，只要是會對於投影到影像感測器3X、4X上的光強度分布進行調變的構成即可，絕對值碼圖案30的構成並沒有特別的限制。In the case of a transmissive encoder, the absolute code pattern 30 may be composed of a transmissive part through which light can pass and a non-transmissive part through which light cannot pass. Regardless of whether it is a reflective encoder or a transmissive encoder, as long as it modulates the light intensity distribution projected onto the image sensors 3X and 4X, the absolute value code pattern 30 does not have a structure. Special restrictions.

另外，實施型態1雖例示從標度尺20的中心沿著徑向，按照發光元件2、影像感測器3X、影像感測器4X的順序依序配置發光元件2及影像感測器3X、4X，但配置的順序並不限於此順序。亦即，只要是要接收的光在標度尺20上的反射位置不同即可，發光元件2及影像感測器3X、4X的配置的順序並沒有限制。In addition, Embodiment 1 illustrates that the light-emitting element 2 , the image sensor 3X , and the image sensor 4X are sequentially arranged along the radial direction from the center of the scale 20 . , 4X, but the configuration order is not limited to this order. That is, as long as the reflection positions of the light to be received on the scale 20 are different, the order in which the light-emitting element 2 and the image sensors 3X and 4X are arranged is not limited.

影像感測器3X、4X及發光元件2係配置成在標度尺20的上表面側朝旋轉軸方向觀看時，會重疊在從標度尺20的中心往標度尺20的第一徑向延伸之半直線上。實施型態1中，將影像感測器3X、4X及發光元件2配置成在從標度尺20的上表面側觀看時，影像感測器3X的中心、影像感測器4X的中心及發光元件2的中心會重疊在該半直線上。The image sensors 3X, 4X and the light-emitting element 2 are arranged so as to overlap in the first radial direction from the center of the scale 20 toward the scale 20 when viewed in the direction of the rotation axis from the upper surface side of the scale 20 Extended half straight line. In Embodiment 1, the image sensors 3X, 4X and the light-emitting element 2 are arranged so that when viewed from the upper surface side of the scale 20, the center of the image sensor 3X, the center of the image sensor 4X and the light-emitting element 2 The center of element 2 will overlap this half line.

就實施型態1而言，影像感測器3X為第一影像感測器，影像感測器4X為第二影像感測器。影像感測器3X係接收來自與標度尺20的中心相距第一距離的第一位置之第一光，而輸出與第一光對應的類比訊號。影像感測器4X係接收來自與標度尺20的中心相距第二距離的第二位置之第二光，而輸出與第二光對應的類比訊號。就實施型態1而言，第一距離與第二距離為不同的距離，影像感測器3X輸出的類比訊號為第一類比訊號，影像感測器4X輸出的類比訊號為第二類比訊號。For implementation type 1, the image sensor 3X is the first image sensor, and the image sensor 4X is the second image sensor. The image sensor 3X receives the first light from a first position at a first distance from the center of the scale 20 and outputs an analog signal corresponding to the first light. The image sensor 4X receives the second light from the second position at a second distance from the center of the scale 20 and outputs an analog signal corresponding to the second light. For implementation type 1, the first distance and the second distance are different distances, the analog signal output by the image sensor 3X is the first analog signal, and the analog signal output by the image sensor 4X is the second analog signal.

AD轉換器5A係將影像感測器3X所檢測出的類比訊號轉換為數位訊號之第一訊號轉換部。AD轉換器5B係將影像感測器4X所檢測出的類比訊號轉換為數位訊號之第二訊號轉換部。AD轉換器5A所轉換出的數位訊號為第一數位訊號，AD轉換器5B所轉換出的數位訊號為第二數位訊號。The AD converter 5A is the first signal conversion unit that converts the analog signal detected by the image sensor 3X into a digital signal. The AD converter 5B is a second signal conversion unit that converts the analog signal detected by the image sensor 4X into a digital signal. The digital signal converted by the AD converter 5A is a first digital signal, and the digital signal converted by the AD converter 5B is a second digital signal.

絕對位置演算部6X係根據AD轉換器5A、5B的輸出來演算出標度尺20的絕對位置之演算部。絕對位置演算部6X係根據第一數位訊號及第二數位訊號而算出在標度尺20上的絕對位置，並將之輸出作為位置資料40X。就實施型態1而言，位置資料40X為第一絕對位置。The absolute position calculation unit 6X calculates the absolute position of the scale 20 based on the outputs of the AD converters 5A and 5B. The absolute position calculation unit 6X calculates the absolute position on the scale 20 based on the first digital signal and the second digital signal, and outputs it as position data 40X. For implementation type 1, the position data 40X is the first absolute position.

絕對位置演算部6X具有光量修正部10A、10B、邊緣檢測部11A、11B、解碼部12A、粗略檢測部13A、相位檢測部14B及高精度檢測部15X。The absolute position calculation unit 6X includes light amount correction units 10A and 10B, edge detection units 11A and 11B, a decoding unit 12A, a rough detection unit 13A, a phase detection unit 14B, and a high-precision detection unit 15X.

光量修正部10A係使從AD轉換器5A傳送來的數位訊號的訊號強度均等化，然後傳送到邊緣檢測部11A。光量修正部10B係使從AD轉換器5B傳送來的數位訊號的訊號強度均等化，然後傳送到邊緣檢測部11B。The light amount correction section 10A equalizes the signal intensity of the digital signal transmitted from the AD converter 5A, and then transmits it to the edge detection section 11A. The light amount correction section 10B equalizes the signal intensity of the digital signal transmitted from the AD converter 5B, and then transmits it to the edge detection section 11B.

邊緣檢測部11A係針對經光量修正部10A使訊號強度均等化後的訊號，求出與預先設定的閾值準位(level)一致之在影像感測器3X上的邊緣位置(以下稱為邊緣像素位置)。另外，邊緣檢測部11A係判別邊緣像素位置為表示邊緣的上升之上升邊緣，還是表示邊緣的下降之下降邊緣。The edge detection unit 11A determines an edge position (hereinafter referred to as an edge pixel) on the image sensor 3X that is consistent with a preset threshold level (level) for the signal whose signal intensity has been equalized by the light amount correction unit 10A. Location). In addition, the edge detection unit 11A determines whether the edge pixel position is a rising edge indicating a rising edge or a falling edge indicating a falling edge.

邊緣檢測部11B係針對經光量修正部10B使訊號強度均等化後的訊號，求出與預先設定的閾值準位(level)一致之在影像感測器4X上的邊緣像素位置。另外，邊緣檢測部11B係判別邊緣像素位置為表示邊緣的上升之上升邊緣，還是表示邊緣的下降之下降邊緣。The edge detection unit 11B determines the edge pixel position on the image sensor 4X that is consistent with a preset threshold level for the signal whose signal intensity has been equalized by the light amount correction unit 10B. In addition, the edge detection unit 11B determines whether the edge pixel position is a rising edge indicating a rising edge or a falling edge indicating a falling edge.

解碼部12A係根據邊緣檢測部11A所判別出的上升邊緣及下降邊緣，將訊號轉換為由位元值「1」及位元值「0」所構成的位元列。The decoding unit 12A converts the signal into a bit sequence composed of a bit value "1" and a bit value "0" based on the rising edge and falling edge determined by the edge detection unit 11A.

粗略檢測部13A係從解碼部12A所轉換出的位元列來檢測出粗略的絕對位置。粗略檢測部13A係例如藉由將表示絕對值碼圖案30的位元列之查找表(look-up table)與解碼部12A所轉換出的位元列相比較，來檢測出粗略的絕對位置。就實施型態1而言，粗略檢測部13A所檢測出的粗略的絕對位置為第二絕對位置。The rough detection unit 13A detects the rough absolute position from the bit string converted by the decoding unit 12A. The rough detection unit 13A detects the rough absolute position, for example, by comparing a look-up table representing the bit string of the absolute value code pattern 30 with the bit string converted by the decoding unit 12A. In Embodiment 1, the rough absolute position detected by the rough detection unit 13A is the second absolute position.

相位檢測部14B係根據邊緣檢測部11B所判別出的上升邊緣及下降邊緣，算出相對於作為基準的像素位置(後述的基準像素位置150)的相位偏移量。The phase detection unit 14B calculates the phase shift amount with respect to a reference pixel position (a reference pixel position 150 described later) based on the rising edge and falling edge determined by the edge detection unit 11B.

高精度檢測部15X係藉由將粗略檢測部13A所檢測出的粗略的絕對位置與相位檢測部14B所算出的相位偏移量予以相加，來算出標度尺20的絕對位置。高精度檢測部15X將算出的絕對位置輸出作為位置資料40X。The high-precision detection unit 15X calculates the absolute position of the scale 20 by adding the rough absolute position detected by the rough detection unit 13A and the phase shift amount calculated by the phase detection unit 14B. The high-precision detection unit 15X outputs the calculated absolute position as position data 40X.

影像感測器3X、4X及發光元件2亦可不是配置成在半直線上重疊。換言之，影像感測器3X、4X亦可不是配置成在從標度尺20的上面側朝旋轉軸方向看時，重疊在從標度尺20的中心往標度尺20的第一徑向延伸之半直線上。亦即，連結影像感測器3X與標度尺20的中心之直線，和連結影像感測器4X與標度尺20的中心之直線可為不同方向的直線。The image sensors 3X, 4X and the light-emitting element 2 may not be arranged to overlap on a half-line. In other words, the image sensors 3X and 4X may not be arranged so as to overlap in the first radial direction extending from the center of the scale 20 toward the scale 20 when viewed from the upper side of the scale 20 toward the rotation axis. half straight line. That is, the straight line connecting the image sensor 3X and the center of the scale 20 and the straight line connecting the image sensor 4X and the center of the scale 20 may be straight lines in different directions.

在影像感測器3X、4X及發光元件2並未重疊在半直線上之情況，絕對位置演算部6X只要使用預先算出的影像感測器3X、4X的相位差來修正從影像感測器3X、4X得到的絕對位置的至少任一方即可。例如，粗略檢測部13A係將從影像感測器3X得到的絕對位置修正為當影像感測器3X、4X及發光元件2被配置於半直線上的情況從影像感測器3X得到的絕對位置。另外，相位檢測部14B將從影像感測器4X得到的相位偏移量修正為當影像感測器3X、4X及發光元件2被配置於半直線上的情況從影像感測器4X得到的相位偏移量。When the image sensors 3X, 4X and the light-emitting element 2 do not overlap on the half-line, the absolute position calculation unit 6X only needs to use the pre-calculated phase difference of the image sensors 3X, 4X to correct the phase difference between the image sensors 3X and 4X. , at least any one of the absolute positions obtained by 4X can be used. For example, the rough detection unit 13A corrects the absolute position obtained from the image sensor 3X to the absolute position obtained from the image sensor 3X when the image sensors 3X, 4X and the light-emitting element 2 are arranged on a semi-line. . In addition, the phase detection unit 14B corrects the phase shift amount obtained from the image sensor 4X to the phase obtained from the image sensor 4X when the image sensors 3X, 4X and the light-emitting element 2 are arranged on a semi-linear line. Offset.

影像感測器3X、4X及發光元件2並未重疊在半直線上之情況，絕對編碼器1X係配置有兩個發光元件2。影像感測器3X接收從兩個發光元件2之中的一個發光元件2發出的光，影像感測器4X接收從兩個發光元件2之中的另一個發光元件2發出的光。When the image sensors 3X, 4X and the light-emitting elements 2 do not overlap on the semi-linear line, the absolute encoder 1X is equipped with two light-emitting elements 2. The image sensor 3X receives the light emitted from one of the two light-emitting elements 2 , and the image sensor 4X receives the light emitted from the other of the two light-emitting elements 2 .

接著，說明絕對位置演算部6X的各構成部的動作。AD轉換器5A將影像感測器3X所檢測出的類比訊號轉換為數位訊號並傳送給光量修正部10A，光量修正部10A就將數位訊號的訊號強度予以均等化後傳送給邊緣檢測部11A。Next, operations of each component of the absolute position calculation unit 6X will be described. The AD converter 5A converts the analog signal detected by the image sensor 3X into a digital signal and sends it to the light quantity correction part 10A. The light quantity correction part 10A equalizes the signal intensity of the digital signal and sends it to the edge detection part 11A.

當AD轉換器5B將影像感測器4X所檢測出的類比訊號轉換為數位訊號並傳送給光量修正部10B，光量修正部10B就將數位訊號的訊號強度予以均等化後傳送給邊緣檢測部11B。When the AD converter 5B converts the analog signal detected by the image sensor 4X into a digital signal and sends it to the light quantity correction part 10B, the light quantity correction part 10B equalizes the signal intensity of the digital signal and sends it to the edge detection part 11B. .

圖2係顯示實施型態1之絕對編碼器的輸入至光量修正部的訊號之圖。圖2的橫軸為像素位置，縱軸為訊號強度。輸入至光量修正部10A、10B之訊號係具有如同光強度分布70之分布。FIG. 2 is a diagram showing a signal input to a light amount correction unit of the absolute encoder according to Embodiment 1. The horizontal axis of Figure 2 is the pixel position, and the vertical axis is the signal intensity. The signals input to the light amount correction sections 10A and 10B have a distribution similar to the light intensity distribution 70 .

輸入至光量修正部10A之訊號與輸入至光量修正部10B之訊號，係為依影像感測器3X、4X的配置位置的差異而不同之訊號。因為影像感測器3X、4X執行相同的處理，光量修正部10A、10B進行相同的處理，邊緣檢測部11A、11B執行相同的處理，所以在圖2至圖5中，只針對影像感測器3X、光量修正部10A、邊緣檢測部11A所進行的處理來做說明。The signal input to the light amount correction section 10A and the signal input to the light amount correction section 10B are different signals depending on the difference in the arrangement positions of the image sensors 3X and 4X. Since the image sensors 3X and 4X perform the same processing, the light amount correction units 10A and 10B perform the same processing, and the edge detection units 11A and 11B perform the same processing, in FIGS. 2 to 5 , only the image sensors are 3X, the processing performed by the light amount correction unit 10A and the edge detection unit 11A will be described.

圖2所示的High位元8係代表標度尺20的反射部31的圖案，Low位元9係代表標度尺20的非反射部32的圖案。投影到影像感測器3X上的與標度尺20的絕對值碼圖案30對應的訊號係如圖2所示，High位元8與Low位元9呈現不均等的光強度分布70。亦即，因為絕對值碼圖案30而產生的訊號會由於發光元件2本身的光強度分布有偏差、影像感測器3X的各像素的增益有偏差等之影響而成為不均等的光強度分布70。因此，光量修正部10A係以讓不均等的光強度分布70成為均等的光強度分布之方式，根據預先計測得到的光量修正值來針對每個像素進行光量的修正。The High bit 8 shown in FIG. 2 represents the pattern of the reflective portion 31 of the scale 20 , and the Low bit 9 represents the pattern of the non-reflective portion 32 of the scale 20 . The signal corresponding to the absolute value code pattern 30 of the scale 20 projected onto the image sensor 3X is as shown in FIG. 2 . The High bit 8 and the Low bit 9 present an uneven light intensity distribution 70 . That is, the signal generated by the absolute value code pattern 30 will become an uneven light intensity distribution 70 due to the influence of the deviation of the light intensity distribution of the light-emitting element 2 itself, the deviation of the gain of each pixel of the image sensor 3X, etc. . Therefore, the light amount correction unit 10A corrects the light amount for each pixel based on the light amount correction value measured in advance so that the uneven light intensity distribution 70 becomes a uniform light intensity distribution.

圖3係顯示實施型態1之絕對編碼器的光量修正部所輸出的訊號之圖。圖3的橫軸為像素位置，縱軸為訊號強度。圖3顯示由光量修正部10A將圖2所示的訊號的光量修正後的訊號的光強度分布71。如圖3所示，經光量修正後，與絕對值碼圖案30對應的訊號係High位元8及Low位元9呈現均等的光強度分布71。光量修正部10A將光強度分布71傳送至邊緣檢測部11A。另外，光量修正部10B將進行過光量的修正之光強度分布傳送至邊緣檢測部11B。FIG. 3 is a diagram showing a signal output by a light amount correction section of the absolute encoder according to Embodiment 1. The horizontal axis of Figure 3 is the pixel position, and the vertical axis is the signal intensity. FIG. 3 shows the light intensity distribution 71 of the signal after the light amount of the signal shown in FIG. 2 is corrected by the light amount correcting unit 10A. As shown in FIG. 3 , after light intensity correction, the signal High bit 8 and Low bit 9 corresponding to the absolute value code pattern 30 present an equal light intensity distribution 71 . The light amount correction part 10A transmits the light intensity distribution 71 to the edge detection part 11A. In addition, the light amount correction section 10B transmits the light intensity distribution with the corrected light amount to the edge detection section 11B.

邊緣檢測部11A針對光強度分布71的訊號，求出與預先設定的閾值準位105一致之在影像感測器3X上的邊緣像素位置(後述的邊緣像素位置110)。圖3中顯示邊緣區域75來作為屬於包含邊緣像素位置的區域之邊緣區域的一例。The edge detection unit 11A determines an edge pixel position on the image sensor 3X (edge pixel position 110 to be described later) consistent with a preset threshold level 105 for the signal of the light intensity distribution 71 . An edge area 75 is shown in FIG. 3 as an example of an edge area belonging to an area including an edge pixel position.

圖4係顯示圖3所示的邊緣區域的訊號之圖。圖4的橫軸為像素位置，縱軸為訊號強度。圖4係顯示圖3所示的邊緣區域75的放大圖。光強度分布71的訊號之中與閾值準位105一致之像素位置為邊緣像素位置110。FIG. 4 is a diagram showing signals in the edge area shown in FIG. 3 . The horizontal axis of Figure 4 is the pixel position, and the vertical axis is the signal intensity. FIG. 4 is an enlarged view of the edge region 75 shown in FIG. 3 . The pixel position in the signal of the light intensity distribution 71 that is consistent with the threshold level 105 is the edge pixel position 110 .

邊緣檢測部11A係檢測出在相隣的第i (i為自然數)個像素的訊號強度與第i＋1個像素的訊號強度之中，一方的訊號強度比閾值準位105低，另一方訊號強度比閾值準位105高之兩個像素。具體而言，邊緣檢測部11A係判斷第i個像素的訊號強度比閾值準位105低，且第i＋1個像素的訊號強度比閾值準位105高之兩個像素間有邊緣像素位置110，邊緣檢測部11A也判斷第i個像素的訊號強度比閾值準位105高，且第i＋1個像素的訊號強度比閾值準位105低之兩個像素間有邊緣像素位置110。The edge detection unit 11A detects that among the signal intensity of the adjacent i-th (i is a natural number) pixel and the signal intensity of the i+1-th pixel, the signal intensity of one is lower than the threshold level 105, and the signal intensity of the other is lower than the threshold level 105. Two pixels above the threshold level of 105. Specifically, the edge detection unit 11A determines that there is an edge pixel position 110 between two pixels where the signal intensity of the i-th pixel is lower than the threshold level 105 and the signal intensity of the i+1-th pixel is higher than the threshold level 105. The detection unit 11A also determines that there is an edge pixel position 110 between two pixels in which the signal intensity of the i-th pixel is higher than the threshold level 105 and the signal intensity of the i+1-th pixel is lower than the threshold level 105.

然後，邊緣檢測部11A針對判定為有邊緣像素位置110之第i個像素與第i＋1個像素，以跨過閾值準位105之方式對第i個像素與第i＋1個像素進行線性內插。邊緣檢測部11A係檢測出經線性內插而得的訊號與閾值準位105之一致點作為邊緣像素位置110。如此的邊緣像素位置110為數位訊號的上升或下降的位置。換言之，邊緣像素位置110係數位訊號之有無的交界。Then, the edge detection unit 11A linearly interpolates the i-th pixel and the i+1-th pixel at the pixel position 110 determined to have an edge so as to cross the threshold level 105. The edge detection unit 11A detects the coincidence point between the linearly interpolated signal and the threshold level 105 as the edge pixel position 110 . Such edge pixel position 110 is the rising or falling position of the digital signal. In other words, the edge pixel position 110 is the boundary between the presence and absence of the signal.

然後，邊緣檢測部11A藉由判定所檢測出的邊緣像素位置110是上升邊緣還是下降邊緣，來檢測出上升邊緣及下降邊緣。Then, the edge detection unit 11A detects a rising edge and a falling edge by determining whether the detected edge pixel position 110 is a rising edge or a falling edge.

圖5係用來說明實施型態1之絕對編碼器的邊緣檢測部所檢測出的上升邊緣及下降邊緣之圖。圖5的橫方向對應於像素位置。FIG. 5 is a diagram illustrating rising edges and falling edges detected by the edge detection unit of the absolute encoder according to Embodiment 1. The horizontal direction of Figure 5 corresponds to the pixel position.

邊緣檢測部11A所檢測出的上升邊緣51，為所檢測出的邊緣像素位置110之中第i個像素的訊號強度比第i＋1個像素的訊號強度低之邊緣像素位置110。The rising edge 51 detected by the edge detection unit 11A is the edge pixel position 110 in which the signal intensity of the i-th pixel is lower than the signal intensity of the i+1-th pixel among the detected edge pixel positions 110.

邊緣檢測部11A所檢測出的下降邊緣52，為所檢測出的邊緣像素位置110之中第i個像素的訊號強度比第i＋1個像素的訊號強度高之邊緣像素位置110。The falling edge 52 detected by the edge detection unit 11A is the edge pixel position 110 in which the signal intensity of the i-th pixel is higher than the signal intensity of the i+1-th pixel among the detected edge pixel positions 110.

藉此，邊緣檢測部11A針對各邊緣像素位置110分別設定表示邊緣像素位置110是上升邊緣51還是下降邊緣52之邊緣方向資訊50。邊緣檢測部11A將邊緣方向資訊50及邊緣像素位置110傳送至解碼部12A。Thereby, the edge detection unit 11A sets edge direction information 50 indicating whether the edge pixel position 110 is a rising edge 51 or a falling edge 52 for each edge pixel position 110 . The edge detection unit 11A transmits the edge direction information 50 and the edge pixel position 110 to the decoding unit 12A.

邊緣檢測部11B也藉由與邊緣檢測部11A相同的處理而得到邊緣方向資訊50及邊緣像素位置110。邊緣檢測部11B將邊緣方向資訊50及邊緣像素位置110傳送至相位檢測部14B。The edge detection unit 11B also obtains the edge direction information 50 and the edge pixel position 110 through the same processing as the edge detection unit 11A. The edge detection part 11B transmits the edge direction information 50 and the edge pixel position 110 to the phase detection part 14B.

解碼部12A係根據邊緣方向資訊50及邊緣像素位置110而將High位元8及Low位元9轉換為「1」或「0」之位元值，藉此將訊號轉換為位元列。The decoding part 12A converts the High bit 8 and the Low bit 9 into bit values of "1" or "0" based on the edge direction information 50 and the edge pixel position 110, thereby converting the signal into a bit sequence.

圖6係顯示與圖5所示的邊緣資訊對應的位元列之圖。圖6係顯示解碼部12A根據邊緣方向資訊50及邊緣像素位置110將High位元8及Low位元9轉換為「1」或「0」而得到的位元列120。FIG. 6 is a diagram showing bit sequences corresponding to the edge information shown in FIG. 5 . FIG. 6 shows the bit sequence 120 obtained by the decoding unit 12A converting the High bit 8 and the Low bit 9 into "1" or "0" according to the edge direction information 50 and the edge pixel position 110.

解碼部12A係例如將從上升邊緣51到下降邊緣52之間設為位元值「1」，將從下降邊緣52到上升邊緣51之間設為位元值「0」來產生出位元列120。經此，High位元8被表現成位元值「1」，Low位元9被表現成位元值「0」。For example, the decoding unit 12A sets the bit value "1" between the rising edge 51 and the falling edge 52 and sets the bit value "0" between the falling edge 52 and the rising edge 51 to generate a bit sequence. 120. After this, High bit 8 is expressed as a bit value "1", and Low bit 9 is expressed as a bit value "0".

而且，解碼部12A係以每一位元的像素的寬度與基本周期寬度相等的方式產生出位元列120。基本周期寬度係由反射部31及非反射部32所構成的絕對值碼圖案30的最小線寬。不過，因為絕對值碼圖案30係從標度尺20的中心呈輻射狀形成，所以基本周期寬度的值係依標度尺20的徑向而改變。Furthermore, the decoding unit 12A generates the bit sequence 120 such that the width of the pixel of each bit is equal to the basic period width. The basic period width is the minimum line width of the absolute value code pattern 30 composed of the reflective portion 31 and the non-reflective portion 32 . However, since the absolute value code pattern 30 is formed radially from the center of the scale 20 , the value of the basic period width changes in accordance with the radial direction of the scale 20 .

解碼部12A可藉二值化處理將High位元8及Low位元9轉換為「1」或「0」之位元值來將訊號轉換為位元列120。解碼部12A只要是可將訊號轉換為由「1」及「0」所構成的位元列120之方法即可，而能夠用任何方法將訊號轉換為位元列120。解碼部12A將位元列120傳送至粗略檢測部13A。The decoding part 12A can convert the signal into the bit sequence 120 by converting the High bit 8 and the Low bit 9 into a bit value of "1" or "0" through a binarization process. The decoding unit 12A can convert the signal into the bit sequence 120 by any method as long as it can convert the signal into the bit sequence 120 composed of "1" and "0". The decoding unit 12A sends the bit sequence 120 to the rough detection unit 13A.

粗略檢測部13A係從解碼部12A所轉換出的位元列120檢測出粗略的絕對位置。粗略檢測部13A係例如預先將構成絕對值碼圖案30之位元列儲存在查找表內。粗略檢測部13A藉由將解碼部12A所檢測出的位元列120與查找表內的位元列相比較來具體指出粗略的絕對位置。粗略檢測部13A根據位元列120為對應於查找表內的哪個位元列，來具體指出粗略的絕對位置。The rough detection unit 13A detects a rough absolute position from the bit sequence 120 converted by the decoding unit 12A. For example, the rough detection unit 13A stores the bit strings constituting the absolute value code pattern 30 in a lookup table in advance. The rough detection unit 13A specifically points out the rough absolute position by comparing the bit string 120 detected by the decoding unit 12A with the bit string in the lookup table. The rough detection unit 13A specifically points out the rough absolute position according to which bit sequence in the lookup table the bit sequence 120 corresponds to.

圖7係用來說明實施型態1之絕對編碼器的粗略檢測部具體指出粗略的絕對位置的處理之圖。粗略檢測部13A係參照查找表130，搜尋出與位元列120一致的位元列140。粗略檢測部13A藉由求出與位元列140相當的絕對位置，來決定出與位元列120對應的粗略的絕對位置。粗略檢測部13A檢測出與位元列120一致的位元列140的位置所對應之位置，作為粗略的絕對位置而檢出。粗略檢測部13A將所具體指出的絕對位置傳送至高精度檢測部15X。FIG. 7 is a diagram for explaining the process of specifying the rough absolute position by the rough detection unit of the absolute encoder according to the first embodiment. The rough detection unit 13A refers to the lookup table 130 and searches for the bit sequence 140 that is consistent with the bit sequence 120 . The rough detection unit 13A determines the rough absolute position corresponding to the bit string 120 by finding the absolute position corresponding to the bit string 140 . The rough detection unit 13A detects a position corresponding to the position of the bit sequence 140 that coincides with the bit sequence 120, and detects it as a rough absolute position. The rough detection section 13A transmits the specified absolute position to the high-precision detection section 15X.

粗略檢測部13A在以相當於位元列140的中央位元之像素位置為基準而具體指出粗略的絕對位置之情況，所具體出的絕對位置係相當於由影像感測器3X取得的中心像素位置之絕對位置。When the rough detection unit 13A specifies a rough absolute position based on the pixel position corresponding to the center bit of the bit sequence 140, the specified absolute position is equivalent to the center pixel acquired by the image sensor 3X. The absolute position of the position.

當相位檢測部14B從邊緣檢測部11B接收到邊緣方向資訊50及邊緣像素位置110，就算出屬於基準的像素位置之基準像素位置與訊號之間的相位偏移量。When the phase detection unit 14B receives the edge direction information 50 and the edge pixel position 110 from the edge detection unit 11B, it calculates the phase offset between the reference pixel position belonging to the reference pixel position and the signal.

圖8係用來說明實施型態1之絕對編碼器的相位檢測部所算出的訊號的相位偏移量之圖。相位檢測部14B係算出影像感測器4X之相對於基準像素位置150的相位偏移量θ。將基準像素位置150的中心位置設成P，將最靠近P之邊緣像素位置110設成ZC(i)時，ZC(i)可用相對於基準像素位置150的相位偏移量θ以下的式(1)來表示。FIG. 8 is a diagram for explaining the phase shift amount of the signal calculated by the phase detection unit of the absolute encoder according to the first embodiment. The phase detection unit 14B calculates the phase shift amount θ of the image sensor 4X relative to the reference pixel position 150 . When the center position of the reference pixel position 150 is set to P and the edge pixel position 110 closest to P is set to ZC(i), ZC(i) can be obtained by the following equation ( 1) to express.

ZC(i)＝P＋θ   ...(1)ZC(i)＝P+θ ...(1)

θ係若相對於基準像素位置150在左邊就為負號，在右邊就為正號。換言之，θ係若在旋轉方向位於基準像素位置150之前的位置就為負號，若在旋轉方向位於基準像素位置150之後的位置就為正號。相位檢測部14B找出邊緣檢測部11B所檢測出的邊緣像素位置110之中與P最靠近的ZC(i)，求出ZC(i)與P的差分來算出相位偏移量θ。If the θ system is on the left relative to the reference pixel position 150, it has a negative sign, and if it is on the right, it has a positive sign. In other words, θ has a negative sign if the position is before the reference pixel position 150 in the rotation direction, and has a positive sign if the position is after the reference pixel position 150 in the rotation direction. The phase detection unit 14B finds the ZC(i) closest to P among the edge pixel positions 110 detected by the edge detection unit 11B, and calculates the difference between ZC(i) and P to calculate the phase shift amount θ.

實施型態1中，相位檢測部14B雖然只使用ZC(i)及P來算出相位偏移量θ，但相位檢測部14B亦可使用所有的邊緣像素位置110，以最小平方法來算出相位偏移量θ。另外，基準像素位置150可為影像感測器4X的中心像素，亦可為左端或右端的像素，基準像素位置150的位置並沒有特別的限制。相位檢測部14B將相位偏移量θ傳送至高精度檢測部15X。In Embodiment 1, although the phase detection unit 14B only uses ZC(i) and P to calculate the phase offset amount θ, the phase detection unit 14B may also use all edge pixel positions 110 to calculate the phase offset using the least squares method. Shift amount θ. In addition, the reference pixel position 150 can be the center pixel of the image sensor 4X, or the pixel at the left end or the right end. The position of the reference pixel position 150 is not particularly limited. The phase detection unit 14B transmits the phase shift amount θ to the high-precision detection unit 15X.

高精度檢測部15X係將粗略檢測部13A所算出的粗略的絕對位置與相位檢測部14B所算出的相位偏移量θ相加，來算出標度尺20的絕對位置。高精度檢測部15X係使在粗略的絕對位置的具體指定中使用的位元所對應的像素位置與在相位偏移量θ的算出中使用的基準像素位置150一致，而算出標度尺20的絕對位置。高精度檢測部15X將算出的絕對位置輸出作為位置資料40X。The high-precision detection unit 15X calculates the absolute position of the scale 20 by adding the rough absolute position calculated by the rough detection unit 13A and the phase shift amount θ calculated by the phase detection unit 14B. The high-precision detection unit 15X calculates the pixel position of the scale 20 by matching the pixel position corresponding to the bit used for specifying the rough absolute position with the reference pixel position 150 used for calculating the phase shift amount θ. absolute position. The high-precision detection unit 15X outputs the calculated absolute position as position data 40X.

如上所述，絕對編碼器1X係就訊號檢測用的圖案而言僅依據絕對值碼圖案30而可檢測出高精度的絕對位置。因此，絕對編碼器1X不用使訊號檢測用的圖案複雜化就可檢測出高可靠性且高解析度的絕對位置。As described above, the absolute encoder 1X can detect a high-precision absolute position based only on the absolute value code pattern 30 as a pattern for signal detection. Therefore, the absolute encoder 1X can detect an absolute position with high reliability and high resolution without complicating the signal detection pattern.

而且，絕對編碼器1X因為使用沿著標度尺20的徑向配置的兩個影像感測器3X、4X，所以可使絕對位置的檢測精度提高。在此，針對絕對編碼器1X使用兩個影像感測器3X、4X可使絕對位置的檢測精度提高的理由進行說明。Furthermore, since the absolute encoder 1X uses two image sensors 3X and 4X arranged along the radial direction of the scale 20, the absolute position detection accuracy can be improved. Here, the reason why the absolute encoder 1X can improve the detection accuracy of the absolute position by using the two image sensors 3X and 4X will be explained.

絕對編碼器1X係如圖1所示，將發光元件2、影像感測器3X、4X配置成在從標度尺20的旋轉軸方向觀看時，相對於標度尺20的徑向，發光元件2的中心、影像感測器3X的中心及影像感測器4X的中心會位在一直線上。而且，影像感測器3X配置於比影像感測器4X要為靠近標度尺20的中心之位置。此處的影像感測器3X、4X為相同規格者。The absolute encoder 1X is, as shown in FIG. 1 , in which the light-emitting element 2 and the image sensors 3X and 4X are arranged so that the light-emitting element 2 and the image sensors 3X and 4X are arranged with respect to the radial direction of the scale 20 when viewed from the direction of the rotation axis of the scale 20 . The center of 2, the center of image sensor 3X and the center of image sensor 4X will be on a straight line. Furthermore, the image sensor 3X is disposed closer to the center of the scale 20 than the image sensor 4X. The image sensors 3X and 4X here have the same specifications.

在此，針對利用AD轉換器5A、5B及絕對位置演算部6X來處理影像感測器3X、4X所接收的光而得到的訊號的特徵進行說明。Here, characteristics of signals obtained by processing light received by the image sensors 3X and 4X using the AD converters 5A and 5B and the absolute position calculation unit 6X will be described.

圖9係用來說明實施型態1之絕對編碼器所得到的訊號的特徵之圖。在圖9的左側所示的標度尺20的一部分，顯示了影像感測器3X所接收的光之在標度尺20上的反射地點160，及影像感測器4X所接收的光之在標度尺20上的反射地點170。在圖9的右側，顯示了投影到影像感測器3X、4X之光的光量修正後的光強度分布72、73。光強度分布72為在反射地點160之光的強度分布，光強度分布73為在反射地點170之光的強度分布。FIG. 9 is a diagram for explaining the characteristics of a signal obtained by the absolute encoder of Embodiment 1. The part of the scale 20 shown on the left side of FIG. 9 shows the reflection location 160 of the light received by the image sensor 3X on the scale 20 and the location of the light received by the image sensor 4X. Reflection location 170 on scale 20. On the right side of FIG. 9 , light intensity distributions 72 and 73 corrected for the amount of light projected onto the image sensors 3X and 4X are shown. The light intensity distribution 72 is the intensity distribution of the light at the reflection point 160 , and the light intensity distribution 73 is the intensity distribution of the light at the reflection point 170 .

在影像感測器3X接收的光的反射地點160，包含比影像感測器4X接收的光的反射地點170多的絕對值碼圖案30。因此，邊緣檢測部11B對於投影到影像感測器3X的光的光強度分布72執行邊緣檢測處理時，會檢測到比對於投影到影像感測器4X的光的光強度分布73之邊緣檢測多的邊緣像素位置110。The reflection point 160 of the light received by the image sensor 3X contains more absolute value code patterns 30 than the reflection point 170 of the light received by the image sensor 4X. Therefore, when the edge detection unit 11B performs edge detection processing on the light intensity distribution 72 of the light projected onto the image sensor 3X, it will detect more edges than on the light intensity distribution 73 of the light projected onto the image sensor 4X. The edge pixel position is 110.

另外，就反射地點160、170所包含的相同的反射部31的線寬或相同的非反射部32的線寬而言，在反射地點160之線寬係比在反射地點170之線寬窄。因此，在光強度分布72之基本周期寬度會比在光強度分布73之基本周期寬度窄。此表示解碼部12A針對光強度分布72而產生的位元列18相較於針對光強度分布73而產生的位元列19，每一位元的像素數較少，位元數(位元長度)較多。亦即，影像感測器4X接收的光相較於影像感測器3X接收的光，每一位元的像素數較多，所以解析度比影像感測器3X接收的光高。另一方面，影像感測器3X接收的光相較於影像感測器4X接收的光，位元數較多，所以可靠度比影像感測器4X接收的光高。In addition, regarding the same line width of the reflective portion 31 or the same line width of the non-reflective portion 32 included in the reflection points 160 and 170 , the line width at the reflection point 160 is narrower than the line width at the reflection point 170 . Therefore, the basic period width of the light intensity distribution 72 will be narrower than the basic period width of the light intensity distribution 73 . This means that the bit sequence 18 generated by the decoding unit 12A for the light intensity distribution 72 has fewer pixels per bit than the bit sequence 19 generated for the light intensity distribution 73. The number of bits (bit length) ) more. That is, the light received by the image sensor 4X has more pixels per bit than the light received by the image sensor 3X, so the resolution is higher than the light received by the image sensor 3X. On the other hand, the light received by the image sensor 3X has more bits than the light received by the image sensor 4X, so the reliability is higher than the light received by the image sensor 4X.

實施型態1之絕對編碼器1X係在絕對位置演算部6X內分別處理影像感測器3X、4X所得到的訊號，然後高精度檢測部15X將分別求出的位置資訊予以相加。In the absolute encoder 1X of Embodiment 1, the signals obtained by the image sensors 3X and 4X are processed separately in the absolute position calculation part 6X, and then the high-precision detection part 15X adds the position information obtained separately.

絕對編碼器1X中，AD轉換器5A將來自影像感測器3X的類比訊號轉換為數位訊號，並輸入至絕對位置演算部6X。絕對位置演算部6X對於來自該AD轉換器5A的數位訊號執行光量修正處理、邊緣檢測處理及解碼處理，再由粗略檢測部13A算出粗略的絕對位置。In the absolute encoder 1X, the AD converter 5A converts the analog signal from the image sensor 3X into a digital signal, and inputs the digital signal to the absolute position calculation unit 6X. The absolute position calculation unit 6X performs light amount correction processing, edge detection processing, and decoding processing on the digital signal from the AD converter 5A, and then the rough detection unit 13A calculates a rough absolute position.

粗略檢測部13A將從影像感測器3X所取得的訊號產生的位元列18與查找表130內儲存的位元列相比較，來具體指出粗略的絕對位置。位元列18的位元數比位元列19多，所以粗略檢測部13A能夠以比使用位元列19的情況多的位元作為比較對象，可提高所算出的絕對位置的可靠性。例如，即使在照射到標度尺20的光因為有異物附著於標度尺20而受到遮擋，使位元列18的一部分的位元發生錯誤之情況，只要作為比較對象之位元數較多，粗略檢測部13A就能夠不受異物附著的影響而決定出絕對位置。The rough detection unit 13A compares the bit sequence 18 generated from the signal acquired by the image sensor 3X with the bit sequence stored in the lookup table 130 to specify the rough absolute position. The bit sequence 18 has more bits than the bit sequence 19 . Therefore, the rough detection unit 13A can use more bits as comparison targets than when using the bit sequence 19 , thereby improving the reliability of the calculated absolute position. For example, even if the light irradiating the scale 20 is blocked due to foreign matter adhering to the scale 20 and causing an error in a part of the bits in the bit sequence 18, as long as the number of bits to be compared is large, , the rough detection unit 13A can determine the absolute position without being affected by the adhesion of foreign matter.

再者，絕對編碼器1X中，AD轉換器5B將來自影像感測器4X的類比訊號轉換為數位訊號，並輸入至絕對位置演算部6X。絕對位置演算部6X對於來自該AD轉換器5B的數位訊號執行光量修正處理及邊緣檢測處理，再由相位檢測部14B算出相位偏移量θ。Furthermore, in the absolute encoder 1X, the AD converter 5B converts the analog signal from the image sensor 4X into a digital signal, and inputs the digital signal to the absolute position calculation unit 6X. The absolute position calculation unit 6X performs light amount correction processing and edge detection processing on the digital signal from the AD converter 5B, and then the phase detection unit 14B calculates the phase shift amount θ.

相位檢測部14B所算出的相位偏移量θ的單位為像素數。影像感測器4X所取得的位元列19的每一位元的像素數比位元列18的每一位元的像素數多。因此，與相位偏移量θ相當的像素數中，位元列19的像素數會比位元列18的像素數多。相位檢測部14B因為是使用位元列19來算出相位偏移量θ，所以可算出比使用位元列18來算出相位偏移量θ的情況高的解析度的相位偏移量θ。The unit of the phase shift amount θ calculated by the phase detection unit 14B is the number of pixels. The number of pixels per bit of the bit sequence 19 acquired by the image sensor 4X is greater than the number of pixels per bit of the bit sequence 18 . Therefore, among the number of pixels corresponding to the phase shift amount θ, the number of pixels in the bit sequence 19 is greater than the number of pixels in the bit sequence 18 . Since the phase detection unit 14B uses the bit sequence 19 to calculate the phase offset amount θ, it can calculate the phase offset amount θ with a higher resolution than when the bit sequence 18 is used to calculate the phase offset amount θ.

高精度檢測部15X係將粗略檢測部13A所算出的可靠性高的粗略的絕對位置與相位檢測部14B所算出的高解析度的相位偏移量θ相加。如上所述，絕對編碼器1X藉由分別處理從影像感測器3X、4X所得到的訊號再予以相加，可得到可靠性高且解析度高之絕對位置。The high-precision detection unit 15X adds the highly reliable rough absolute position calculated by the rough detection unit 13A and the high-resolution phase shift amount θ calculated by the phase detection unit 14B. As mentioned above, the absolute encoder 1X can obtain an absolute position with high reliability and high resolution by separately processing the signals obtained from the image sensors 3X and 4X and then adding them together.

如上所述，絕對編碼器1X因為是根據在絕對值碼圖案30之中的兩處計測的兩個訊號來算出位置資料40X，所以可得到可靠性高且解析度高的絕對位置。As described above, the absolute encoder 1X calculates the position data 40X based on the two signals measured at two places in the absolute value code pattern 30, so it can obtain an absolute position with high reliability and high resolution.

而且，因為絕對編碼器1X可得到可靠性高且解析度高的絕對位置，所以不須使AD轉換器5A、5B的解析度提高，也不須增加檢測次數。Furthermore, since the absolute encoder 1X can obtain an absolute position with high reliability and high resolution, it is not necessary to increase the resolution of the AD converters 5A and 5B or to increase the number of detections.

又，因為絕對編碼器1X的標度尺20係在沿著圓周的方向只設置一道具有絕對值碼圖案30之軌跡(track)，所以可用簡單的構成得到可靠性高且解析度高的絕對位置。In addition, since the scale 20 of the absolute encoder 1X is provided with only one track having the absolute value code pattern 30 along the circumferential direction, an absolute position with high reliability and high resolution can be obtained with a simple structure. .

實施型態1雖然是針對使用相同規格的影像感測器3X、4X之情況進行說明，但只要滿足位元列18的位元數比位元列19的位元數多之條件即可，亦可採用比影像感測器4X小型的影像感測器3X。如此，可減小絕對編碼器1X的安裝體積。此外，絕對編碼器1X亦可使用三個以上的影像感測器來檢測絕對位置。Although Embodiment 1 is described for the case of using image sensors 3X and 4X with the same specifications, it only needs to satisfy the condition that the number of bits in bit sequence 18 is greater than the number of bits in bit sequence 19. Image sensor 3X, which is smaller than image sensor 4X, can be used. In this way, the installation volume of the absolute encoder 1X can be reduced. In addition, the absolute encoder 1X can also use more than three image sensors to detect absolute position.

如上所述的實施型態1之絕對編碼器1X，影像感測器3X、4X係配置成重疊在從標度尺20的中心往徑向延伸之半直線上。而且，絕對位置演算部6X係根據來自影像感測器3X的訊號而算出標度尺20上的粗略的絕對位置，以及根據來自影像感測器4X的訊號而算出相對於基準像素位置150的相位偏移量θ。以及，絕對位置演算部6X係將粗略的絕對位置與相位偏移量θ相加起來以算出位置資料40X。因此，絕對位置演算部6X可將根據可靠度高的粗略的資訊而算出的絕對位置與根據解析度高的資訊而算出的相位偏移量θ相加，而可算出可靠性高且解析度高的位置資料40X。As described above, in the absolute encoder 1X of Embodiment 1, the image sensors 3X and 4X are arranged so as to overlap on the half straight line extending in the radial direction from the center of the scale 20 . Furthermore, the absolute position calculation unit 6X calculates the rough absolute position on the scale 20 based on the signal from the image sensor 3X, and calculates the phase relative to the reference pixel position 150 based on the signal from the image sensor 4X. Offset θ. In addition, the absolute position calculation unit 6X adds the rough absolute position and the phase shift amount θ to calculate the position data 40X. Therefore, the absolute position calculation unit 6X can add the absolute position calculated based on highly reliable rough information and the phase shift amount θ calculated based on high-resolution information, and can calculate a highly reliable and high-resolution calculation. Location information 40X.

實施型態2. 接著，利用圖10及圖11來說明實施型態2。實施型態2中，絕對位置演算部係產生將使用從一方的影像感測器取得的訊號而算出的位元列與使用從另一方的影像感測器取得的訊號而算出的位元列相接而成的位元列，來算出粗略的絕對位置。 Implementation type 2. Next, Embodiment 2 will be described using FIGS. 10 and 11 . In Embodiment 2, the absolute position calculation unit generates a bit string calculated using a signal obtained from one image sensor and a bit string calculated using a signal obtained from the other image sensor. The concatenated bit sequence is used to calculate the rough absolute position.

圖10係顯示實施型態2之絕對編碼器的構成之圖。圖11係用來說明實施型態2之絕對編碼器中的影像感測器的配置位置之圖。圖10的各構成元件之中達成與圖1所示的實施型態1之絕對編碼器1X相同機能之構成元件都標以相同符號，而將重複的說明省略。FIG. 10 is a diagram showing the structure of an absolute encoder according to Embodiment 2. FIG. 11 is a diagram illustrating the arrangement position of the image sensor in the absolute encoder according to Embodiment 2. Among the structural elements in FIG. 10 , the structural elements that achieve the same functions as those of the absolute encoder 1X of Embodiment 1 shown in FIG. 1 are denoted by the same reference numerals, and repeated descriptions will be omitted.

絕對編碼器1Y係具備有發光元件2、影像感測器3Y、4Y、標度尺20、AD轉換器5A、5B及絕對位置演算部6Y。影像感測器3Y、4Y為與影像感測器3X、4X相同的影像感測器，相較於影像感測器3X、4X係沿著標度尺20的圓周的方向的配置位置不同。The absolute encoder 1Y includes a light-emitting element 2, image sensors 3Y and 4Y, a scale 20, AD converters 5A and 5B, and an absolute position calculation unit 6Y. The image sensors 3Y and 4Y are the same image sensors as the image sensors 3X and 4X, but are arranged in a different position along the circumferential direction of the scale 20 than the image sensors 3X and 4X.

絕對位置演算部6Y係具有光量修正部10A、10B、邊緣檢測部11A、11B、解碼部12A、12B、粗略檢測部13Y、相位檢測部14A、14B、高精度檢測部15A、15B及演算部45。The absolute position calculation unit 6Y includes light amount correction units 10A and 10B, edge detection units 11A and 11B, decoding units 12A and 12B, rough detection units 13Y, phase detection units 14A and 14B, high-precision detection units 15A and 15B, and a calculation unit 45 .

絕對編碼器1Y中，影像感測器3Y的中心Ca與影像感測器4Y的中心Cb係相對於沿著標度尺20的圓周的方向位於不同的位置。換言之，絕對編碼器1Y中，影像感測器3Y、4Y係配置成在從上表面側觀看標度尺20時，影像感測器3Y的中心Ca以外的位置及影像感測器4Y的中心Cb以外的位置的至少其中一方，係重疊在從標度尺20的中心C1往標度尺20的第一徑向延伸之半直線22上。亦即，影像感測器3Y、4Y係配置成：影像感測器3Y的一部分及影像感測器4Y的一部分係重疊在半直線22上，且影像感測器3Y的中心Ca及影像感測器4Y的中心Cb的至少其中一方並不重疊在半直線22上。發光元件2係配置成發光元件2的中心C2重疊在該半直線22上。從中心Ca到半直線22的最短距離與從中心Cb到半直線22的最短距離係相同。In the absolute encoder 1Y, the center Ca of the image sensor 3Y and the center Cb of the image sensor 4Y are located at different positions relative to the circumferential direction of the scale 20 . In other words, in the absolute encoder 1Y, the image sensors 3Y and 4Y are arranged so that when the scale 20 is viewed from the upper surface side, positions other than the center Ca of the image sensor 3Y and the center Cb of the image sensor 4Y are At least one of the other positions overlaps with the half straight line 22 extending from the center C1 of the scale 20 toward the first radial direction of the scale 20 . That is, the image sensors 3Y and 4Y are configured such that a part of the image sensor 3Y and a part of the image sensor 4Y overlap on the half line 22, and the center Ca of the image sensor 3Y and the image sensor At least one of the centers Cb of the device 4Y does not overlap with the half straight line 22 . The light-emitting element 2 is arranged so that the center C2 of the light-emitting element 2 overlaps the half straight line 22 . The shortest distance from the center Ca to the half straight line 22 is the same as the shortest distance from the center Cb to the half straight line 22 .

另外，在絕對編碼器1Y中，影像感測器3Y、4Y係配置成連結發光元件2的中心C2與標度尺20的中心C1之半直線22會通過影像感測器3Y的受光面21A及影像感測器4Y的受光面21B。並且，在絕對編碼器1Y中，影像感測器3Y、4Y還配置成影像感測器3Y的在長度方向延伸的中央線41與影像感測器4Y的在長度方向延伸的中央線42並不重疊。影像感測器3Y、4Y的長度方向係與半直線22垂直之方向。就實施型態2而言，影像感測器3Y為第一影像感測器，影像感測器4Y為第二影像感測器。In addition, in the absolute encoder 1Y, the image sensors 3Y and 4Y are arranged so that the half straight line 22 connecting the center C2 of the light-emitting element 2 and the center C1 of the scale 20 passes through the light-receiving surface 21A of the image sensor 3Y and The light-receiving surface 21B of the image sensor 4Y. Furthermore, in the absolute encoder 1Y, the image sensors 3Y and 4Y are arranged so that the center line 41 extending in the longitudinal direction of the image sensor 3Y and the center line 42 extending in the longitudinal direction of the image sensor 4Y are not in contact with each other. overlap. The length direction of the image sensors 3Y and 4Y is perpendicular to the half-line 22 . For implementation type 2, the image sensor 3Y is the first image sensor, and the image sensor 4Y is the second image sensor.

如上所述，在絕對編碼器1Y中，影像感測器3Y、4Y配置成影像感測器3Y、4Y之在沿著圓周的方向上的位置及徑向的位置不相同，且半直線22通過受光面21A、21B。As described above, in the absolute encoder 1Y, the image sensors 3Y and 4Y are arranged so that the positions of the image sensors 3Y and 4Y in the circumferential direction and the radial direction are different, and the half straight line 22 passes through Light receiving surfaces 21A, 21B.

如此的影像感測器3Y、4Y的配置，使得受光面21A、21B接收的光會有一部分包含共通的絕對值碼圖案。因此，絕對編碼器1Y可得到將藉由對影像感測器3Y、4Y的訊號進行解碼而得到的位元列相接而成的位元列23。Such a configuration of the image sensors 3Y and 4Y causes a part of the light received by the light receiving surfaces 21A and 21B to contain a common absolute value code pattern. Therefore, the absolute encoder 1Y can obtain the bit sequence 23 formed by concatenating the bit sequences obtained by decoding the signals of the image sensors 3Y and 4Y.

絕對位置演算部6Y中，光量修正部10A、邊緣檢測部11A、解碼部12A、相位檢測部14A及高精度檢測部15A分別執行與光量修正部10B、邊緣檢測部11B、解碼部12B、相位檢測部14B及高精度檢測部15B相同的處理。因此，此處只針對光量修正部10A、邊緣檢測部11A、解碼部12A、相位檢測部14A及高精度檢測部15A所執行的處理進行說明。另外，針對粗略檢測部13Y及演算部45所執行的處理進行說明。In the absolute position calculation unit 6Y, the light amount correction unit 10A, the edge detection unit 11A, the decoding unit 12A, the phase detection unit 14A, and the high-precision detection unit 15A respectively execute the light amount correction unit 10B, the edge detection unit 11B, the decoding unit 12B, and the phase detection. The same process is performed by the section 14B and the high-precision detection section 15B. Therefore, only the processing performed by the light amount correction unit 10A, the edge detection unit 11A, the decoding unit 12A, the phase detection unit 14A, and the high-precision detection unit 15A will be described here. In addition, the processing executed by the rough detection unit 13Y and the calculation unit 45 will be described.

絕對位置演算部6Y的光量修正部10A、邊緣檢測部11A、解碼部12A、 粗略檢測部13Y、相位檢測部14A及高精度檢測部15A分別執行與絕對位置演算部6X的光量修正部10A、邊緣檢測部11A、解碼部12A、粗略檢測部13A、相位檢測部14B及高精度檢測部15X相同的處理。The light amount correction unit 10A, the edge detection unit 11A, the decoding unit 12A, the rough detection unit 13Y, the phase detection unit 14A, and the high-precision detection unit 15A of the absolute position calculation unit 6Y respectively perform the same tasks as the light amount correction unit 10A and the edge of the absolute position calculation unit 6X. The detection unit 11A, the decoding unit 12A, the rough detection unit 13A, the phase detection unit 14B, and the high-precision detection unit 15X perform the same processing.

亦即，光量修正部10A係使從AD轉換器5A傳送來的數位訊號的訊號強度均等化，然後傳送到邊緣檢測部11A。邊緣檢測部11A係針對訊號強度經均等化後的訊號，求出與閾值準位105一致之邊緣像素位置110。另外，邊緣檢測部11A將表示邊緣的上升或下降之邊緣方向資訊50設定給各邊緣像素位置110。絕對位置演算部6Y的邊緣檢測部11A將邊緣方向資訊50及邊緣像素位置110傳送至解碼部12A及相位檢測部14A。That is, the light amount correction part 10A equalizes the signal intensity of the digital signal transmitted from the AD converter 5A, and then transmits it to the edge detection part 11A. The edge detection unit 11A obtains an edge pixel position 110 consistent with the threshold level 105 for the signal whose signal intensity has been equalized. In addition, the edge detection unit 11A sets edge direction information 50 indicating rising or falling edges to each edge pixel position 110 . The edge detection unit 11A of the absolute position calculation unit 6Y transmits the edge direction information 50 and the edge pixel position 110 to the decoding unit 12A and the phase detection unit 14A.

解碼部12A係根據邊緣方向資訊50及邊緣像素位置110將訊號轉換為由位元值「1」及位元值「0」所構成的位元列。解碼部12A將位元列傳送至粗略檢測部13Y。The decoding part 12A converts the signal into a bit sequence composed of a bit value "1" and a bit value "0" based on the edge direction information 50 and the edge pixel position 110. The decoding unit 12A sends the bit sequence to the rough detection unit 13Y.

解碼部12B係進行與解碼部12A一樣的處理。亦即，解碼部12B根據從邊緣檢測部11B接收到的邊緣方向資訊50及邊緣像素位置110，將訊號轉換為由位元值「1」及位元值「0」所構成的位元列。解碼部12B將位元列傳送至粗略檢測部13Y。The decoding unit 12B performs the same processing as the decoding unit 12A. That is, the decoding unit 12B converts the signal into a bit sequence composed of a bit value “1” and a bit value “0” based on the edge direction information 50 and edge pixel position 110 received from the edge detection unit 11B. The decoding unit 12B sends the bit sequence to the rough detection unit 13Y.

粗略檢測部13Y係將解碼部12A所轉換出的位元列與解碼部12B所轉換出的位元列相接而產生位元列23。粗略檢測部13Y藉由將位元列23與查找表130相比較來檢測出粗略的絕對位置。此時，粗略檢測部13Y係以讓所具體指出的粗略的絕對位置成為半直線22上的標度尺角度位置之方式調整粗略的絕對位置而檢測出粗略的絕對位置。就實施型態2而言，粗略檢測部13Y所檢測出的粗略的絕對位置為第二絕對位置。粗略檢測部13Y將調整後的粗略的絕對位置傳送至高精度檢測部15A、15B。The rough detection part 13Y connects the bit sequence converted by the decoding part 12A and the bit sequence converted by the decoding part 12B to generate the bit sequence 23. The rough detection unit 13Y detects a rough absolute position by comparing the bit sequence 23 with the lookup table 130 . At this time, the rough detection unit 13Y adjusts the rough absolute position so that the specified rough absolute position becomes the scale angle position on the half straight line 22 to detect the rough absolute position. In Embodiment 2, the rough absolute position detected by the rough detection unit 13Y is the second absolute position. The rough detection unit 13Y transmits the adjusted rough absolute position to the high-precision detection units 15A and 15B.

相位檢測部14A係根據邊緣檢測部11A所判別出的上升邊緣51及下降邊緣52，來算出相對於基準像素位置24之相位偏移量θ。此時，相位檢測部14A係以讓影像感測器3Y的基準像素位置成為半直線22上的基準像素位置24之方式調整相位偏移量θ而算出相位偏移量θ。相位檢測部14A將相位偏移量θ傳送至高精度檢測部15A。The phase detection unit 14A calculates the phase shift amount θ with respect to the reference pixel position 24 based on the rising edge 51 and the falling edge 52 determined by the edge detection unit 11A. At this time, the phase detection unit 14A adjusts the phase offset amount θ so that the reference pixel position of the image sensor 3Y becomes the reference pixel position 24 on the half line 22 to calculate the phase offset amount θ. The phase detection unit 14A transmits the phase shift amount θ to the high-precision detection unit 15A.

相位檢測部14B係根據邊緣檢測部11B所判別出的上升邊緣51及下降邊緣52，來算出相對於基準像素位置25之相位偏移量θ。此時，相位檢測部14B係以讓影像感測器4Y的基準像素位置成為半直線22上的基準像素位置25之方式調整相位偏移量θ而算出相位偏移量θ。相位檢測部14B將相位偏移量θ傳送至高精度檢測部15B。The phase detection unit 14B calculates the phase shift amount θ with respect to the reference pixel position 25 based on the rising edge 51 and the falling edge 52 determined by the edge detection unit 11B. At this time, the phase detection unit 14B adjusts the phase offset amount θ so that the reference pixel position of the image sensor 4Y becomes the reference pixel position 25 on the half line 22 to calculate the phase offset amount θ. The phase detection unit 14B transmits the phase shift amount θ to the high-precision detection unit 15B.

就實施型態2而言，基準像素位置24為第一基準像素位置，相位檢測部14A所算出的相位偏移量θ為第一相位偏移量。並且，在實施型態2中，基準像素位置25為第二基準像素位置，相位檢測部14B所算出的相位偏移量θ為第二相位偏移量。In Embodiment 2, the reference pixel position 24 is the first reference pixel position, and the phase shift amount θ calculated by the phase detection unit 14A is the first phase shift amount. Furthermore, in Embodiment 2, the reference pixel position 25 is the second reference pixel position, and the phase shift amount θ calculated by the phase detection unit 14B is the second phase shift amount.

高精度檢測部15A係藉由將粗略檢測部13Y所檢測出的粗略的絕對位置與相位檢測部14A所算出的相位偏移量θ相加，來算出標度尺20的絕對位置。高精度檢測部15A將算出的絕對位置傳送至演算部45。The high-precision detection unit 15A calculates the absolute position of the scale 20 by adding the rough absolute position detected by the rough detection unit 13Y and the phase shift amount θ calculated by the phase detection unit 14A. The high-precision detection unit 15A transmits the calculated absolute position to the calculation unit 45 .

高精度檢測部15B係與高精度檢測部15A相同地，藉由將粗略檢測部13Y所檢測出的粗略的絕對位置與相位檢測部14B所算出的相位偏移量θ相加，來算出標度尺20的絕對位置。高精度檢測部15B將算出的絕對位置傳送至演算部45。Like the high-precision detection unit 15A, the high-precision detection unit 15B calculates the scale by adding the rough absolute position detected by the rough detection unit 13Y and the phase shift amount θ calculated by the phase detection unit 14B. The absolute position of feet 20. The high-precision detection unit 15B transmits the calculated absolute position to the calculation unit 45 .

就實施型態2而言，高精度檢測部15A所算出的絕對位置為第三絕對位置，高精度檢測部15B所算出的絕對位置為第四絕對位置。In Embodiment 2, the absolute position calculated by the high-precision detection unit 15A is the third absolute position, and the absolute position calculated by the high-precision detection unit 15B is the fourth absolute position.

如上所述，影像感測器3Y所取得的訊號經過從光量修正部10A到高精度檢測部15A的處理而演算為標度尺20的絕對位置，影像感測器4Y所取得的訊號經過從光量修正部10B到高精度檢測部15B的處理而演算為標度尺20的絕對位置。As described above, the signal acquired by the image sensor 3Y is processed from the light amount correction part 10A to the high-precision detection part 15A and calculated into the absolute position of the scale 20 . The signal acquired by the image sensor 4Y is processed from the light amount. The correction unit 10B performs processing to the high-precision detection unit 15B to calculate the absolute position of the scale 20 .

演算部45係算出高精度檢測部15A所算出的絕對位置與高精度檢測部15B所算出的絕對位置的平均位置，並將算出的平均位置輸出作為位置資料40Y。就實施型態2而言，位置資料40Y為第一絕對位置。The calculation unit 45 calculates the average position of the absolute position calculated by the high-precision detection unit 15A and the absolute position calculated by the high-precision detection unit 15B, and outputs the calculated average position as position data 40Y. For implementation type 2, the position data 40Y is the first absolute position.

如上所述的實施型態2之絕對位置演算部6Y，因為粗略檢測部13Y係產生將解碼部12A所轉換出的位元列與解碼部12B所轉換出的位元列相接而成的位元列23並算出絕對位置，所以可得到可靠性高的絕對位置。As described above, in the absolute position calculation unit 6Y of the second embodiment, the rough detection unit 13Y generates a bit sequence formed by concatenating the bit sequence converted by the decoding unit 12A and the bit sequence converted by the decoding unit 12B. The element column 23 is used to calculate the absolute position, so a highly reliable absolute position can be obtained.

實施型態3. 接著，利用圖12至圖16來說明實施型態3。實施型態3之絕對編碼器係將兩個影像感測器配置於中間隔著標度尺20的中心而相對向的位置。實施型態3之絕對編碼器，係在兩個影像感測器之中的一個角度檢測功能為異常之情況，輸出從正常的影像感測器得到的絕對位置，在兩個的角度檢測功能都正常之情況輸出絕對位置的平均位置。 Implementation type 3. Next, Embodiment 3 will be described using FIGS. 12 to 16 . The absolute encoder of Embodiment 3 arranges two image sensors at opposite positions with the center of the scale 20 in between. The absolute encoder of implementation type 3 outputs the absolute position obtained from the normal image sensor when one of the angle detection functions of the two image sensors is abnormal. Normally, the average position of the absolute position is output.

圖12係顯示實施型態3之絕對編碼器的構成之圖。圖12的各構成元件之中，關於達成與圖1所示的實施型態1之絕對編碼器1X或圖10所示的實施型態2之絕對編碼器1Y相同功能之構成元件都標以相同符號，並將重複的說明省略。Fig. 12 is a diagram showing the structure of an absolute encoder according to Embodiment 3. Among the components shown in FIG. 12 , components that achieve the same functions as the absolute encoder 1X according to the first embodiment shown in FIG. 1 or the absolute encoder 1Y according to the second embodiment shown in FIG. 10 are denoted by the same symbols. symbol, and duplicate descriptions are omitted.

絕對編碼器1Z係具備有發光元件2A、2B、影像感測器3Z、4Z、標度尺20、AD轉換器5A、5B及絕對位置演算部6Z。影像感測器3Z、4Z為與影像感測器3X、4X相同的影像感測器，與影像感測器3X、4X不同之處在於配置位置不同。The absolute encoder 1Z includes light-emitting elements 2A and 2B, image sensors 3Z and 4Z, a scale 20, AD converters 5A and 5B, and an absolute position calculation unit 6Z. The image sensors 3Z and 4Z are the same image sensors as the image sensors 3X and 4X. The difference from the image sensors 3X and 4X lies in the different arrangement positions.

實施型態3中，影像感測器3Z、4Z係配置於相對於旋轉軸7的轉軸呈對稱且相差180°的位置。換言之，影像感測器3Z、4Z係配置成於中間隔著標度尺20的中心位置並相對向。In the third embodiment, the image sensors 3Z and 4Z are arranged at positions that are symmetrical and 180° different from the rotation axis of the rotation axis 7 . In other words, the image sensors 3Z and 4Z are arranged at the center position of the scale 20 and face each other.

發光元件2A、2B係與實施型態1的發光元件2相同為照射光至標度尺20之照明部。影像感測器3Z係接收發光元件2A所照射並於標度尺20反射的光，並將與接收的光對應的類比訊號輸出至AD轉換器5A。影像感測器4Z係接收發光元件2B所照射並於標度尺20反射的光，並將與接收的光對應的類比訊號輸出至AD轉換器5B。Like the light-emitting element 2 of Embodiment 1, the light-emitting elements 2A and 2B are illumination portions that irradiate light to the scale 20 . The image sensor 3Z receives the light irradiated by the light-emitting element 2A and reflected on the scale 20, and outputs an analog signal corresponding to the received light to the AD converter 5A. The image sensor 4Z receives the light irradiated by the light-emitting element 2B and reflected on the scale 20, and outputs an analog signal corresponding to the received light to the AD converter 5B.

就實施型態3而言，發光元件2A為照射光到標度尺20的第一位置之第一發光元件，發光元件2B為照射光到標度尺20的第二位置之第二發光元件。再者，在實施型態3中，影像感測器3Z為第一影像感測器，影像感測器4Z為第二影像感測器。影像感測器3Z係接收來自與標度尺20的中心相距第一距離的第一位置之第一光而輸出與第一光對應的類比訊號。影像感測器4Z係接收來自與標度尺20的中心相距第二距離的第二位置之第二光而輸出與第二光對應的類比訊號。實施型態3中，第一距離與第二距離可為不同的距離，亦可為相同的距離。影像感測器3Z輸出的類比訊號為第一類比訊號，影像感測器4Z輸出的類比訊號為第二類比訊號。In Embodiment 3, the light-emitting element 2A is a first light-emitting element that irradiates light to the first position of the scale 20 , and the light-emitting element 2B is a second light-emitting element that irradiates light to the second position of the scale 20 . Furthermore, in Embodiment 3, the image sensor 3Z is a first image sensor, and the image sensor 4Z is a second image sensor. The image sensor 3Z receives the first light from a first position at a first distance from the center of the scale 20 and outputs an analog signal corresponding to the first light. The image sensor 4Z receives the second light from the second position that is a second distance away from the center of the scale 20 and outputs an analog signal corresponding to the second light. In the third embodiment, the first distance and the second distance may be different distances or may be the same distance. The analog signal output by the image sensor 3Z is the first analog signal, and the analog signal output by the image sensor 4Z is the second analog signal.

絕對位置演算部6Z係具有光量修正部10A、10B、邊緣檢測部11A、11B、解碼部12A、12B、粗略檢測部13A、13B、相位檢測部14A、14B、高精度檢測部15A、15B及位置資料產生部16。The absolute position calculation unit 6Z includes light amount correction units 10A, 10B, edge detection units 11A, 11B, decoding units 12A, 12B, rough detection units 13A, 13B, phase detection units 14A, 14B, high-precision detection units 15A, 15B, and position Data generation department 16.

粗略檢測部13A係藉由將解碼部12A所轉換出的位元列與查找表130相比較來檢測出粗略的絕對位置。粗略檢測部13A將調整後的粗略的絕對位置傳送至高精度檢測部15A。The rough detection unit 13A detects the rough absolute position by comparing the bit sequence converted by the decoding unit 12A with the lookup table 130 . The rough detection unit 13A transmits the adjusted rough absolute position to the high-precision detection unit 15A.

粗略檢測部13B係藉由將解碼部12B所轉換出的位元列與查找表130相比較來檢測出粗略的絕對位置。粗略檢測部13B將調整後的粗略的絕對位置傳送至高精度檢測部15B。The rough detection unit 13B detects the rough absolute position by comparing the bit sequence converted by the decoding unit 12B with the lookup table 130 . The rough detection unit 13B transmits the adjusted rough absolute position to the high-precision detection unit 15B.

高精度檢測部15A係藉由將粗略檢測部13A所檢測出的粗略的絕對位置與相位檢測部14A所算出的相位偏移量θ相加，來算出標度尺20的絕對位置。高精度檢測部15A將算出的絕對位置傳送至位置資料產生部16。The high-precision detection unit 15A calculates the absolute position of the scale 20 by adding the rough absolute position detected by the rough detection unit 13A and the phase shift amount θ calculated by the phase detection unit 14A. The high-precision detection unit 15A transmits the calculated absolute position to the position data generation unit 16 .

高精度檢測部15B係藉由將粗略檢測部13B所檢測出的粗略的絕對位置與相位檢測部14B所算出的相位偏移量θ相加，來算出標度尺20的絕對位置。高精度檢測部15B將算出的絕對位置傳送至位置資料產生部16。The high-precision detection unit 15B calculates the absolute position of the scale 20 by adding the rough absolute position detected by the rough detection unit 13B and the phase shift amount θ calculated by the phase detection unit 14B. The high-precision detection unit 15B transmits the calculated absolute position to the position data generation unit 16 .

如上所述，絕對位置演算部6Z個別處理影像感測器3Z所取得的訊號及影像感測器4Z所取得的訊號，並從各自的訊號算出絕對位置。亦即，絕對位置演算部6Z經由從光量修正部10A到高精度檢測部15A的處理，從影像感測器3Z所取得的訊號算出絕對位置。以及，絕對位置演算部6Z經由從光量修正部10B到高精度檢測部15B的處理，從影像感測器4Z所取得的訊號算出絕對位置。As described above, the absolute position calculation unit 6Z processes the signal acquired by the image sensor 3Z and the signal acquired by the image sensor 4Z individually, and calculates the absolute position from the respective signals. That is, the absolute position calculation unit 6Z calculates the absolute position from the signal acquired by the image sensor 3Z through processing from the light amount correction unit 10A to the high-precision detection unit 15A. And the absolute position calculation unit 6Z calculates the absolute position from the signal acquired by the image sensor 4Z through processing from the light amount correction unit 10B to the high-precision detection unit 15B.

位置資料產生部16係算出影像感測器3Z的絕對位置與影像感測器4Z的絕對位置的平均位置並將之輸出以作為位置資料40Z。就實施型態3而言，影像感測器3Z的絕對位置為第二絕對位置，影像感測器4Z的絕對位置為第三絕對位置。另外，在實施型態3中，位置資料40Z為第一絕對位置。The position data generating unit 16 calculates the average position of the absolute position of the image sensor 3Z and the absolute position of the image sensor 4Z and outputs it as the position data 40Z. For the third embodiment, the absolute position of the image sensor 3Z is the second absolute position, and the absolute position of the image sensor 4Z is the third absolute position. In addition, in Embodiment 3, the position data 40Z is the first absolute position.

圖13係實施型態3之絕對編碼器的位置資料產生部所進行的位置資料的產生處理步驟之流程圖。位置資料產生部16係將高精度檢測部15A所算出的絕對位置及高精度檢測部15B所算出的絕對位置的相位差與以修正(步驟S10)。高精度檢測部15A所算出的絕對位置為從影像感測器3Z得到的絕對位置，高精度檢測部15B所算出的絕對位置為從影像感測器4Z得到的絕對位置。位置資料產生部16使用預先算出的影像感測器3Z、4Z的相位差，來修正從影像感測器3Z、4Z得到的絕對位置的至少其中一方。Fig. 13 is a flowchart of the position data generation processing steps performed by the position data generation unit of the absolute encoder according to Embodiment 3. The position data generating unit 16 corrects the phase difference between the absolute position calculated by the high-precision detection unit 15A and the absolute position calculated by the high-precision detection unit 15B (step S10). The absolute position calculated by the high-precision detection unit 15A is the absolute position obtained from the image sensor 3Z, and the absolute position calculated by the high-precision detection unit 15B is the absolute position obtained from the image sensor 4Z. The position data generating unit 16 corrects at least one of the absolute positions obtained from the image sensors 3Z and 4Z using the precalculated phase difference between the image sensors 3Z and 4Z.

位置資料產生部16判定絕對編碼器1Z有無異常(步驟S20)。絕對編碼器1Z之異常係影像感測器3Z的角度檢測功能及影像感測器4Z的角度檢測功能的至少其中一方之異常。位置資料產生部16檢測到異常時，就使絕對編碼器1Z的動作緊急停止，或將絕對位置修正為正常的絕對位置並繼續動作。The position data generating unit 16 determines whether there is an abnormality in the absolute encoder 1Z (step S20). The abnormality of the absolute encoder 1Z is an abnormality of at least one of the angle detection function of the image sensor 3Z and the angle detection function of the image sensor 4Z. When the position data generating unit 16 detects an abnormality, it causes an emergency stop of the operation of the absolute encoder 1Z, or corrects the absolute position to a normal absolute position and continues operation.

圖14係實施型態3之絕對編碼器的位置資料產生部所進行的異常判定處理的第一例的處理步驟之流程圖。位置資料產生部16在修正相位差之後判定從影像感測器3Z、4Z得到的絕對位置的差分是否為差分的基準值以上(步驟S110)。FIG. 14 is a flowchart of the processing steps of the first example of abnormality determination processing performed by the position data generating unit of the absolute encoder according to the third embodiment. After correcting the phase difference, the position data generation unit 16 determines whether the difference in absolute positions obtained from the image sensors 3Z and 4Z is greater than or equal to a reference value of the difference (step S110).

若絕對位置的差分為差分的基準值以上(步驟S110的結果為“是”)，則位置資料產生部16判定為絕對編碼器1Z的異常。亦即，位置資料產生部16判定為影像感測器3Z的角度檢測功能及影像感測器4Z的角度檢測功能的至少其中一方為異常。在此情況，位置資料產生部16使讓旋轉軸7旋轉之馬達緊急停止來使標度尺20的旋轉緊急停止(步驟S120)。具體而言，在絕對位置的差分為差分的基準值以上之情況，位置資料產生部16將用來使馬達緊急停止的指令發送至控制馬達之馬達控制裝置。藉此，馬達控制裝置就使馬達停止。If the difference in absolute position is greater than or equal to the reference value of the difference (the result of step S110 is "YES"), the position data generating unit 16 determines that there is an abnormality in the absolute encoder 1Z. That is, the position data generating unit 16 determines that at least one of the angle detection function of the image sensor 3Z and the angle detection function of the image sensor 4Z is abnormal. In this case, the position data generating unit 16 makes an emergency stop of the motor that rotates the rotating shaft 7 to make an emergency stop of the rotation of the scale 20 (step S120). Specifically, when the difference in absolute position is equal to or greater than the reference value of the difference, the position data generating unit 16 sends a command for emergency stopping of the motor to the motor control device that controls the motor. Thereby, the motor control device stops the motor.

另一方面，若絕對位置的差分小於差分的基準值(步驟S110的結果為“否”)，則位置資料產生部16判定為絕對編碼器1Z正常。在此情況，位置資料產生部16將從影像感測器3Z、4Z得到的修正過相位差的絕對位置的平均位置輸出作為位置資料40Z (步驟S130)。以此方式，絕對編碼器1Z可用簡單的演算得到可靠性高的絕對位置。On the other hand, if the difference in absolute position is less than the reference value of the difference (the result of step S110 is "NO"), the position data generating unit 16 determines that the absolute encoder 1Z is normal. In this case, the position data generation unit 16 outputs the average position of the phase difference corrected absolute positions obtained from the image sensors 3Z and 4Z as the position data 40Z (step S130). In this way, the absolute encoder 1Z can obtain an absolute position with high reliability through simple calculation.

圖15係實施型態3之絕對編碼器的位置資料產生部所進行的異常判定處理的第二例的處理步驟之流程圖。位置資料產生部16判定影像感測器3Z的角度檢測功能是否異常(步驟S210)。位置資料產生部16係例如在邊緣檢測部11A所檢測出的邊緣像素位置110的個數為邊緣數的基準值以下之情況判定為異常。此外，位置資料產生部16亦可在粗略檢測部13A所求出的位元列120與查找表130內的位元列140的差異位元數為閾值以上之情況判定為異常。FIG. 15 is a flowchart of a processing procedure of a second example of abnormality determination processing performed by the position data generating unit of the absolute encoder according to Embodiment 3. The position data generation unit 16 determines whether the angle detection function of the image sensor 3Z is abnormal (step S210). For example, the position data generation unit 16 determines that it is abnormal when the number of edge pixel positions 110 detected by the edge detection unit 11A is less than or equal to a reference value for the number of edges. In addition, the location data generation unit 16 may also determine that the difference in bits between the bit sequence 120 calculated by the rough detection unit 13A and the bit sequence 140 in the lookup table 130 is greater than or equal to a threshold as an abnormality.

在影像感測器3Z的角度檢測功能為異常之情況(步驟S210的結果為“是”)，位置資料產生部16判定影像感測器4Z的角度檢測功能是否異常(步驟S220)。位置資料產生部16係例如在邊緣檢測部11B所檢測出的邊緣像素位置110的個數為邊緣數的基準值以下之情況判定為異常。在影像感測器3Z之邊緣像素位置110為第一邊緣位置，在影像感測器4Z之邊緣像素位置110為第二邊緣位置。When the angle detection function of the image sensor 3Z is abnormal (the result of step S210 is "YES"), the position data generation unit 16 determines whether the angle detection function of the image sensor 4Z is abnormal (step S220). For example, the position data generation unit 16 determines that it is abnormal when the number of edge pixel positions 110 detected by the edge detection unit 11B is less than or equal to a reference value for the number of edges. The edge pixel position 110 of the image sensor 3Z is the first edge position, and the edge pixel position 110 of the image sensor 4Z is the second edge position.

此外，位置資料產生部16亦可在粗略檢測部13B所求出的位元列120與查找表130內的位元列140的差異位元數為閾值以上之情況判定為異常。就實施型態3而言，粗略檢測部13A所求出的位元列120為第一位元列，粗略檢測部13B所求出的位元列120為第二位元列。並且，查找表130內的位元列140為第三位元列。再者，在實施型態3中，影像感測器3Z的角度檢測功能為第一角度檢測功能，影像感測器4Z的角度檢測功能為第二角度檢測功能。In addition, the location data generation unit 16 may determine that the difference in bits between the bit string 120 obtained by the rough detection unit 13B and the bit string 140 in the lookup table 130 is greater than or equal to a threshold as an abnormality. In the third embodiment, the bit sequence 120 obtained by the rough detection unit 13A is the first bit sequence, and the bit sequence 120 obtained by the rough detection unit 13B is the second bit sequence. Furthermore, the bit sequence 140 in the lookup table 130 is the third bit sequence. Furthermore, in Embodiment 3, the angle detection function of the image sensor 3Z is the first angle detection function, and the angle detection function of the image sensor 4Z is the second angle detection function.

在影像感測器4Z的角度檢測功能為異常之情況(步驟S220的結果為“是”)，位置資料產生部16使馬達緊急停止(步驟S230)。When the angle detection function of the image sensor 4Z is abnormal (the result of step S220 is "YES"), the position data generating unit 16 causes the motor to emergency stop (step S230).

在影像感測器3Z的角度檢測功能為異常，但影像感測器4Z的角度檢測功能並非異常之情況(步驟S220的結果為“否”)，位置資料產生部16將從影像感測器4Z得到的絕對位置輸出作為位置資料40Z (步驟S240)。亦即，位置資料產生部16將從高精度檢測部15B傳送來的絕對位置輸出作為位置資料40Z。When the angle detection function of the image sensor 3Z is abnormal but the angle detection function of the image sensor 4Z is not abnormal (the result of step S220 is "No"), the position data generation unit 16 will generate the data from the image sensor 4Z. The obtained absolute position is output as position data 40Z (step S240). That is, the position data generation unit 16 outputs the absolute position transmitted from the high-precision detection unit 15B as the position data 40Z.

在影像感測器3Z的角度檢測功能並非異常之情況(步驟S210的結果為“否”)，位置資料產生部16判定影像感測器4Z的角度檢測功能是否異常(步驟S250)。此處之位置資料產生部16亦可在邊緣檢測部11B所檢測出的邊緣像素位置110的個數為邊緣數的基準值以下之情況判定為異常，在位元列120與位元列140的差異位元數為閾值以上之情況判定為異常。When the angle detection function of the image sensor 3Z is not abnormal (the result of step S210 is "No"), the position data generation unit 16 determines whether the angle detection function of the image sensor 4Z is abnormal (step S250). Here, the position data generation unit 16 may also determine that it is abnormal when the number of edge pixel positions 110 detected by the edge detection unit 11B is less than the reference value of the number of edges. If the number of difference bits exceeds the threshold, it is determined to be abnormal.

在影像感測器3Z的角度檢測功能並非異常，但影像感測器4Z的角度檢測功能為異常之情況(步驟S250的結果為“是”)，位置資料產生部16將從影像感測器3Z得到的絕對位置輸出作為位置資料40Z (步驟S260)。亦即，位置資料產生部16將從高精度檢測部15A傳送來的絕對位置輸出作為位置資料40Z。When the angle detection function of the image sensor 3Z is not abnormal, but the angle detection function of the image sensor 4Z is abnormal (the result of step S250 is "Yes"), the position data generation unit 16 will generate the data from the image sensor 3Z. The obtained absolute position is output as position data 40Z (step S260). That is, the position data generation unit 16 outputs the absolute position transmitted from the high-precision detection unit 15A as the position data 40Z.

在影像感測器3Z、4Z的角度檢測功能並非異常之情況(步驟S250的結果為“否”)，位置資料產生部16將從影像感測器3Z、4Z得到的絕對位置的平均位置輸出作為位置資料40Z (步驟S270)。亦即，位置資料產生部16將從高精度檢測部15A、15B傳送來的絕對位置的平均位置輸出作為位置資料40Z。When the angle detection functions of the image sensors 3Z and 4Z are not abnormal (the result of step S250 is "No"), the position data generation unit 16 outputs the average position of the absolute positions obtained from the image sensors 3Z and 4Z as Location data 40Z (step S270). That is, the position data generation unit 16 outputs the average position of the absolute positions transmitted from the high-precision detection units 15A and 15B as the position data 40Z.

如上所述，因為位置資料產生部16判定影像感測器3Z、4Z的角度檢測功能是否異常，且只要有正常的角度檢測功能就繼續動作，所以絕對編碼器1Z可穩健地得到絕對位置。As described above, the position data generating unit 16 determines whether the angle detection functions of the image sensors 3Z and 4Z are abnormal and continues to operate as long as there is a normal angle detection function, so the absolute encoder 1Z can obtain the absolute position reliably.

另外，在絕對編碼器1Z中，以180°之相位差配置影像感測器3Z、4Z。而且，絕對編碼器1Z產生出利用影像感測器3Z、4Z而得到的絕對位置的平均位置作為位置資料40Z。因此，絕對編碼器1Z可去除由於旋轉的標度尺20的面偏擺而產生的絕對位置的誤差成分。In addition, in the absolute encoder 1Z, the image sensors 3Z and 4Z are arranged with a phase difference of 180°. Furthermore, the absolute encoder 1Z generates the average position of the absolute positions obtained by the image sensors 3Z and 4Z as the position data 40Z. Therefore, the absolute encoder 1Z can remove the error component of the absolute position caused by the surface deflection of the rotating scale 20 .

圖16係用來說明實施型態3之絕對編碼器的標度尺發生的面偏擺之圖。絕對編碼器1Z中，將標度尺20的上表面與控制基板27的上表面配置成相向。Fig. 16 is a diagram illustrating surface deflection occurring in the scale of the absolute encoder according to Embodiment 3. In the absolute encoder 1Z, the upper surface of the scale 20 and the upper surface of the control board 27 are arranged to face each other.

發光元件2A、2B及影像感測器3Z、4Z係配置在控制基板27的上表面。圖16顯示標度尺20因為面偏擺而相對於控制基板27傾斜的情況。此外，也有控制基板27相對於標度尺20而傾斜的情況。The light-emitting elements 2A and 2B and the image sensors 3Z and 4Z are arranged on the upper surface of the control substrate 27 . FIG. 16 shows a case where the scale 20 is tilted relative to the control substrate 27 due to surface deflection. In addition, the control substrate 27 may be tilted relative to the scale 20 .

如上所述的實施型態3之絕對編碼器1Z，因為影像感測器3Z、4Z以180°的相位差配置，所以影像感測器3Z與標度尺20之間的距離和影像感測器4Z與標度尺20之間的距離之和，不會受標度尺20的旋轉位置影響而為一定。因此，絕對位置演算部6Z可藉由以從影像感測器3Z、4Z得到的絕對位置的平均位置作為位置資料40Z，而去除因面偏擺而產生的絕對位置的誤差成分。As described above, in the absolute encoder 1Z of Embodiment 3, since the image sensors 3Z and 4Z are arranged with a phase difference of 180°, the distance between the image sensor 3Z and the scale 20 is less than the distance between the image sensor 3Z and the scale 20. The sum of the distances between 4Z and the scale 20 is constant regardless of the rotational position of the scale 20 . Therefore, the absolute position calculation unit 6Z can remove the error component of the absolute position caused by the surface deflection by using the average position of the absolute positions obtained from the image sensors 3Z and 4Z as the position data 40Z.

此外，影像感測器3Z與標度尺20之間的距離和影像感測器4Z與標度尺20之間的距離亦可不同。即使在此情況，絕對位置演算部6Z也一樣可藉由以從影像感測器3Z、4Z得到的絕對位置的平均位置作為位置資料40Z，而去除因面偏擺而產生的絕對位置的誤差成分。In addition, the distance between the image sensor 3Z and the scale 20 and the distance between the image sensor 4Z and the scale 20 may also be different. Even in this case, the absolute position calculation unit 6Z can remove the error component of the absolute position caused by the surface deflection by using the average position of the absolute positions obtained from the image sensors 3Z and 4Z as the position data 40Z. .

實施型態4. 接著，利用圖17至圖21來說明實施型態4。實施型態4係將發光元件2及影像感測器3X、4X安裝於一個模組。 Implementation type 4. Next, Embodiment 4 will be described using FIGS. 17 to 21 . Implementation type 4 is to install the light-emitting element 2 and the image sensors 3X and 4X in one module.

圖17係顯示實施型態4之絕對編碼器的概略構成之圖。圖17的各構成元件之中達成與圖1所示的實施型態1之絕對編碼器1X相同功能之構成元件都標以相同符號，並將重複的說明省略。FIG. 17 is a diagram showing the schematic configuration of an absolute encoder according to Embodiment 4. Among the components in FIG. 17 , components that achieve the same functions as those of the absolute encoder 1X of Embodiment 1 shown in FIG. 1 are denoted by the same reference numerals, and repeated descriptions are omitted.

實施型態4之絕對編碼器1X係具有與實施型態1之絕對編碼器1X相同的構成元件。實施型態4之絕對編碼器1X中，將發光元件2及影像感測器3X、4X係整合成一個模組80a，安裝於構成絕對編碼器1X的硬體之控制基板27上。具體而言，發光元件2及影像感測器3X、4X係安裝在小基板26上，該小基板26再安裝於控制基板27的上表面。The absolute encoder 1X of the fourth embodiment has the same components as the absolute encoder 1X of the first embodiment. In the absolute encoder 1X of the fourth embodiment, the light-emitting element 2 and the image sensors 3X and 4X are integrated into a module 80a, which is installed on the control substrate 27 that constitutes the hardware of the absolute encoder 1X. Specifically, the light-emitting element 2 and the image sensors 3X and 4X are mounted on the small substrate 26 , and the small substrate 26 is mounted on the upper surface of the control substrate 27 .

在此，針對模組80a的構成以及在與模組80a不同的位置之配置有發光元件2或影像感測器3X、4X之模組80b、80c的構成進行說明。Here, the structure of the module 80a and the structures of the modules 80b and 80c in which the light-emitting element 2 or the image sensors 3X and 4X are arranged at different positions from the module 80a will be described.

圖18係顯示實施型態4之絕對編碼器的安裝有影像感測器的模組的第一構成例之圖。圖18顯示在從影像感測器3X、4X的安裝方向觀看模組80a時之模組80a的頂面圖。FIG. 18 is a diagram showing a first structural example of a module equipped with an image sensor of the absolute encoder according to Embodiment 4. FIG. 18 shows a top view of the module 80a when the module 80a is viewed from the installation direction of the image sensors 3X and 4X.

圖19係顯示實施型態4之絕對編碼器的安裝有影像感測器的模組的第二構成例之圖。圖19顯示在從影像感測器3P、4P的安裝方向觀看模組80b時之模組80b的頂面圖。模組80b可適用於在實施型態1中說明過的絕對編碼器1X等。FIG. 19 is a diagram showing a second structural example of a module equipped with an image sensor of the absolute encoder according to Embodiment 4. FIG. 19 shows a top view of the module 80b when the module 80b is viewed from the installation direction of the image sensors 3P and 4P. The module 80b can be applied to the absolute encoder 1X described in Embodiment 1, etc.

圖20係顯示實施型態4之絕對編碼器的安裝有影像感測器的模組的第三構成例之圖。圖20顯示在從影像感測器3Z的安裝方向觀看模組80c時之模組80c的頂面圖。模組80c可適用於在實施型態3中說明過的絕對編碼器1Z等。FIG. 20 is a diagram showing a third structural example of a module equipped with an image sensor of the absolute encoder according to Embodiment 4. FIG. 20 shows a top view of the module 80c when the module 80c is viewed from the installation direction of the image sensor 3Z. The module 80c can be applied to the absolute encoder 1Z described in Embodiment 3, etc.

模組80a中，發光元件2及影像感測器3X、4X係配置於小基板26的上表面。模組80a中，影像感測器4X配置在與發光元件2相對向的位置，影像感測器3X配置於發光元件2與影像感測器4X之間。In the module 80a, the light-emitting element 2 and the image sensors 3X and 4X are arranged on the upper surface of the small substrate 26. In the module 80a, the image sensor 4X is arranged at a position opposite to the light-emitting element 2, and the image sensor 3X is arranged between the light-emitting element 2 and the image sensor 4X.

模組80b中，發光元件2及影像感測器3P、4P係配置於小基板26的上表面。影像感測器3P、4P為與影像感測器3X、4X一樣的影像感測器，與影像感測器3X、4X不同之處在於配置位置不同。模組80b中，影像感測器3P、4P配置成影像感測器3P與影像感測器4P為相對向，且發光元件2配置於影像感測器3P與影像感測器4P之間。In the module 80b, the light-emitting element 2 and the image sensors 3P and 4P are arranged on the upper surface of the small substrate 26. The image sensors 3P and 4P are the same image sensors as the image sensors 3X and 4X. The difference from the image sensors 3X and 4X lies in the different arrangement positions. In the module 80b, the image sensors 3P and 4P are arranged such that the image sensor 3P and the image sensor 4P face each other, and the light-emitting element 2 is arranged between the image sensor 3P and the image sensor 4P.

模組80c中，發光元件2A及影像感測器3Z係配置於小基板26的上表面。模組80c中，影像感測器3Z配置在與發光元件2A相對向的位置。另外，發光元件2B及影像感測器4Z係配置於與圖20所示的小基板26不同的小基板26的上表面。In the module 80c, the light-emitting element 2A and the image sensor 3Z are arranged on the upper surface of the small substrate 26. In the module 80c, the image sensor 3Z is arranged at a position opposite to the light-emitting element 2A. In addition, the light-emitting element 2B and the image sensor 4Z are arranged on the upper surface of the small substrate 26 that is different from the small substrate 26 shown in FIG. 20 .

圖21係顯示將圖20所示的模組適用於實施型態3之絕對編碼器的情況之絕對編碼器的構成之圖。圖21中，於上段顯示絕對編碼器1Z所具備的控制基板27等的剖面圖，於下段顯示絕對編碼器1Z所具備的控制基板27的頂面圖。FIG. 21 is a diagram showing the structure of an absolute encoder when the module shown in FIG. 20 is applied to the absolute encoder of Embodiment 3. In FIG. 21 , the upper section shows a cross-sectional view of the control board 27 and the like included in the absolute encoder 1Z, and the lower section shows a top view of the control board 27 included in the absolute encoder 1Z.

在控制基板27的上表面，模組80c、80c配置成隔著標度尺20的中心而相對向。一方的模組80c係利用圖20說明過的模組，安裝有發光元件2A及影像感測器3Z。在另一方的模組80c，影像感測器4Z安裝在與發光元件2B相對向的位置。On the upper surface of the control substrate 27 , the modules 80 c and 80 c are arranged to face each other across the center of the scale 20 . One module 80c is the module explained using FIG. 20, and has the light-emitting element 2A and the image sensor 3Z mounted thereon. In the other module 80c, the image sensor 4Z is installed at a position facing the light-emitting element 2B.

此外，亦可將在實施型態2中說明過的絕對編碼器1Y的發光元件2及影像感測器3Y、4Y安裝於一個模組。如此的絕對編碼器1X、1Y、1Z係將至少一個發光元件及至少一個影像感測器安裝於一個模組。In addition, the light-emitting element 2 of the absolute encoder 1Y described in Embodiment 2 and the image sensors 3Y and 4Y may be mounted in one module. Such absolute encoders 1X, 1Y, and 1Z have at least one light-emitting element and at least one image sensor installed in one module.

根據如此的實施型態4，可藉由使用模組80a、80b、80c的任一者來實現整合安裝零件，可抑制壓縮控制基板27的安裝面積。另外，因為能夠以模組的型態安裝零件，所以可提高生產時的安裝速度，且可減低安裝時的安裝位置錯誤。According to Embodiment 4, integration of mounting parts can be realized by using any one of the modules 80a, 80b, and 80c, and the mounting area of the compression control board 27 can be suppressed. In addition, because parts can be installed in the form of modules, the installation speed during production can be increased and installation position errors during installation can be reduced.

在此，針對絕對位置演算部6X～6Z的硬體構成進行說明。因為絕對位置演算部6X～6Z具有同樣的硬體構成，所以此處只針對絕對位置演算部6X的硬體構成進行說明。Here, the hardware configuration of the absolute position calculation units 6X to 6Z will be described. Since the absolute position calculation units 6X to 6Z have the same hardware structure, only the hardware structure of the absolute position calculation unit 6X will be described here.

圖22係顯示實現實施型態1之絕對編碼器所具備的絕對位置演算部的硬體構成例之圖。絕對位置演算部6X可藉由輸入裝置300、處理器100、記憶體200及輸出裝置400而實現。處理器100之例為CPU (Central Processing Unit：中央處理單元，也稱為處理裝置、演算裝置、微處理器、微電腦、DSP (Digital Signal Processor：數位訊號處理器))或系統LSI (Large Scale Integration：大型積體電路)。記憶體200之例為RAM (Random Access Memory：隨機存取記憶體)、ROM (Read Only Memory：唯讀記憶體)。FIG. 22 is a diagram showing an example of the hardware configuration for realizing the absolute position calculation unit included in the absolute encoder according to Embodiment 1. The absolute position calculation unit 6X can be realized by the input device 300, the processor 100, the memory 200, and the output device 400. An example of the processor 100 is a CPU (Central Processing Unit, also known as a processing device, arithmetic device, a microprocessor, a microcomputer, a DSP (Digital Signal Processor)) or a system LSI (Large Scale Integration). : Large integrated circuit). Examples of the memory 200 are RAM (Random Access Memory) and ROM (Read Only Memory).

藉由處理器100讀出並執行記憶體200中儲存的用來執行絕對位置演算部6X的動作之電腦可執行的絕對位置演算程式，而實現絕對位置演算部6X。作為用來執行絕對位置演算部6X的動作的程式之絕對位置演算程式，也稱為使電腦執行絕對位置演算部6X的步驟或方法之程式。The absolute position calculation unit 6X is realized by the processor 100 reading and executing a computer-executable absolute position calculation program stored in the memory 200 for executing the operations of the absolute position calculation unit 6X. The absolute position calculation program, which is a program for executing the operation of the absolute position calculation unit 6X, is also called a program that causes the computer to execute the steps or methods of the absolute position calculation unit 6X.

在絕對位置演算部6X執行的絕對位置演算程式，係為包含光量修正部10A、10B、邊緣檢測部11A、11B、解碼部12A、粗略檢測部13A、相位檢測部14B、高精度檢測部15X之模組構成，各部分被載入(load)到主記憶裝置上，在主記憶裝置上產生上述各部。The absolute position calculation program executed in the absolute position calculation unit 6X includes light amount correction units 10A and 10B, edge detection units 11A and 11B, decoding unit 12A, rough detection unit 13A, phase detection unit 14B, and high-precision detection unit 15X. The module is constituted, and each part is loaded into the main memory device, and the above-mentioned parts are generated on the main memory device.

輸入裝置300係從AD轉換器5A、5B接收數位訊號並將之傳送至處理器100。記憶體200係被使用為處理器100執行各種處理之際的暫時記憶體。並且，記憶體200係記憶閾值準位105、查找表130等。輸出裝置400係將處理器100所算出的位置資料40X輸出。The input device 300 receives digital signals from the AD converters 5A and 5B and transmits them to the processor 100 . The memory 200 is used as a temporary memory when the processor 100 performs various processes. In addition, the memory 200 stores the threshold level 105, the lookup table 130, and the like. The output device 400 outputs the position data 40X calculated by the processor 100.

絕對位置演算程式能夠以可安裝的形式或可執行的形式之檔案(file)之方式儲存於電腦可讀取的記憶媒體，並以電腦程式產品的型態提供。絕對位置演算程式亦可透過網際網路(Internet)等之網路而提供給絕對位置演算部6X。絕對位置演算部6X的功能可一部分由專用電路等之專用的硬體實現，一部分由軟體或韌體實現。The absolute position calculation program can be stored in a computer-readable memory medium in the form of an installable or executable file, and is provided in the form of a computer program product. The absolute position calculation program can also be provided to the absolute position calculation unit 6X through a network such as the Internet. Part of the function of the absolute position calculation unit 6X can be realized by dedicated hardware such as a dedicated circuit, and part of it can be realized by software or firmware.

以上的實施型態揭示的構成僅為一例，還可與別的公知的技術組合，亦可將實施型態彼此組合，亦可在未脫離主旨的範圍內將構成的一部分省略、變更。The configuration disclosed in the above embodiments is only an example, and may be combined with other known technologies, the embodiments may be combined with each other, and part of the configuration may be omitted or changed within the scope that does not deviate from the gist.

1X,1Y,1Z:絕對編碼器 2,2A,2B:發光元件 3P,3X,3Y,3Z,4P,4X,4Y,4Z:影像感測器 5A,5B:AD轉換器 6X～6Z:絕對位置演算部 7:旋轉軸 8:High位元 9:Low位元 10A,10B:光量修正部 11A,11B:邊緣檢測部 12A,12B:解碼部 13A,13B,13Y:粗略檢測部 14A,14B:相位檢測部 15A,15B,15X:高精度檢測部 16:位置資料產生部 18:位元列 19:位元列 20:標度尺 21A,21B:受光面 22:半直線 23:位元列 24,25:基準像素位置 26:小基板 27:控制基板 30:絕對值碼圖案 31:反射部 32:非反射部 40X,40Y,40Z:位置資料 41:中央線 42:中央線 45:演算部 50:邊緣方向資訊 51:上升邊緣 70～73:光強度分布 75:邊緣區域 80a,80b,80c:模組 100:處理器 105:閾值準位 110:邊緣像素位置 120:位元列 130:查找表 140:位元列 150:基準像素位置 160,170:反射地點 200:記憶體 300:輸入裝置 400:輸出裝置 1X, 1Y, 1Z: Absolute encoder 2,2A,2B:Light-emitting element 3P, 3X, 3Y, 3Z, 4P, 4X, 4Y, 4Z: Image sensor 5A, 5B: AD converter 6X～6Z: Absolute position calculation unit 7:Rotation axis 8:High bit 9:Low bits 10A, 10B: Light intensity correction section 11A, 11B: Edge detection part 12A, 12B: Decoding department 13A, 13B, 13Y: Rough inspection department 14A, 14B: Phase detection part 15A, 15B, 15X: High-precision detection department 16:Location data generation department 18:Bit column 19:Bit column 20: Scale 21A, 21B: light receiving surface 22: Semi-straight line 23:Bit column 24,25: reference pixel position 26:Small substrate 27:Control substrate 30: Absolute value code pattern 31:Reflection part 32:Non-reflective part 40X, 40Y, 40Z: location data 41:Central Line 42:Central Line 45:Calculation Department 50: Edge direction information 51: rising edge 70～73:Light intensity distribution 75: Edge area 80a,80b,80c:module 100:processor 105:Threshold level 110: Edge pixel position 120:Bit column 130:Lookup table 140:Bit column 150: base pixel position 160,170: Reflection location 200:Memory 300:Input device 400:Output device

圖1係顯示實施型態1之絕對編碼器的構成之圖。 圖2係顯示實施型態1之絕對編碼器的輸入至光量修正部的訊號之圖。 圖3係顯示實施型態1之絕對編碼器的光量修正部所輸出的訊號之圖。 圖4係顯示圖3所示的邊緣區域的訊號之圖。 圖5係用來說明實施型態1之絕對編碼器的邊緣檢測部所檢測出的上升邊緣及下降邊緣之圖。 圖6係顯示與圖5所示的邊緣資訊對應的位元列之圖。 圖7係用來說明實施型態1之絕對編碼器的粗略檢測部決定出粗略的絕對位置的處理之圖。 圖8係用來說明實施型態1之絕對編碼器的相位檢測部所算出的訊號的相位偏移量之圖。 圖9係用來說明實施型態1之絕對編碼器所得到的訊號的特徵之圖。 圖10係顯示實施型態2之絕對編碼器的構成之圖。 圖11係用來說明實施型態2之絕對編碼器中的影像感測器的配置位置之圖。 圖12係顯示實施型態3之絕對編碼器的構成之圖。 圖13係顯示實施型態3之絕對編碼器的位置資料產生部所進行的位置資料的產生處理步驟之流程圖。 圖14係顯示實施型態3之絕對編碼器的位置資料產生部所進行的異常判定處理的第一例的處理步驟之流程圖。 圖15係顯示實施型態3之絕對編碼器的位置資料產生部所進行的異常判定處理的第二例的處理步驟之流程圖。 圖16係用來說明實施型態3之絕對編碼器的標度尺發生的面偏擺之圖。 圖17係顯示實施型態4之絕對編碼器的概略構成之圖。 圖18係顯示實施型態4之絕對編碼器的安裝有影像感測器的模組的第一構成例之圖。 圖19係顯示實施型態4之絕對編碼器的安裝有影像感測器的模組的第二構成例之圖。 圖20係顯示實施型態4之絕對編碼器的安裝有影像感測器的模組的第三構成例之圖。 圖21係顯示將圖20所示的模組應用於實施型態3之絕對編碼器的情況的絕對編碼器的構成之圖。 圖22係顯示實現實施型態1之絕對編碼器所具備的絕對位置演算部的硬體構成例之圖。 FIG. 1 is a diagram showing the structure of an absolute encoder according to Embodiment 1. FIG. 2 is a diagram showing a signal input to a light amount correction unit of the absolute encoder according to Embodiment 1. FIG. 3 is a diagram showing a signal output by a light amount correction section of the absolute encoder according to Embodiment 1. FIG. 4 is a diagram showing signals in the edge area shown in FIG. 3 . FIG. 5 is a diagram illustrating rising edges and falling edges detected by the edge detection unit of the absolute encoder according to Embodiment 1. FIG. 6 is a diagram showing bit sequences corresponding to the edge information shown in FIG. 5 . FIG. 7 is a diagram for explaining the process of determining a rough absolute position by the rough detection unit of the absolute encoder according to the first embodiment. FIG. 8 is a diagram for explaining the phase shift amount of the signal calculated by the phase detection unit of the absolute encoder according to the first embodiment. FIG. 9 is a diagram for explaining the characteristics of a signal obtained by the absolute encoder of Embodiment 1. FIG. 10 is a diagram showing the structure of an absolute encoder according to Embodiment 2. FIG. 11 is a diagram illustrating the arrangement position of the image sensor in the absolute encoder according to Embodiment 2. Fig. 12 is a diagram showing the structure of an absolute encoder according to Embodiment 3. FIG. 13 is a flowchart showing the steps of position data generation processing performed by the position data generation unit of the absolute encoder according to Embodiment 3. FIG. 14 is a flowchart showing the processing steps of the first example of abnormality determination processing performed by the position data generating unit of the absolute encoder according to the third embodiment. FIG. 15 is a flowchart showing a processing procedure of a second example of abnormality determination processing performed by the position data generating unit of the absolute encoder according to Embodiment 3. Fig. 16 is a diagram illustrating surface deflection occurring in the scale of the absolute encoder according to Embodiment 3. FIG. 17 is a diagram showing the schematic configuration of an absolute encoder according to Embodiment 4. FIG. 18 is a diagram showing a first structural example of a module equipped with an image sensor of the absolute encoder according to Embodiment 4. FIG. 19 is a diagram showing a second structural example of a module equipped with an image sensor of the absolute encoder according to Embodiment 4. FIG. 20 is a diagram showing a third structural example of a module equipped with an image sensor of the absolute encoder according to Embodiment 4. FIG. 21 is a diagram showing the structure of an absolute encoder when the module shown in FIG. 20 is applied to the absolute encoder of Embodiment 3. FIG. 22 is a diagram showing an example of the hardware configuration for realizing the absolute position calculation unit included in the absolute encoder according to Embodiment 1.

1X:絕對編碼器 1X: Absolute encoder

2:發光元件 2:Light-emitting components

3X,4X:影像感測器 3X, 4X: Image sensor

5A,5B:AD轉換器 5A, 5B: AD converter

6X:絕對位置演算部 6X: Absolute position calculation department

7:旋轉軸 7:Rotation axis

10A,10B:光量修正部 10A, 10B: Light intensity correction section

11A,11B:邊緣檢測部 11A, 11B: Edge detection part

12A:解碼部 12A: Decoding Department

13A:粗略檢測部 13A: Rough inspection department

14B:相位檢測部 14B: Phase detection part

15X:高精度檢測部 15X: High-precision detection department

20:標度尺 20: Scale

30:絕對值碼圖案 30: Absolute value code pattern

31:反射部 31:Reflection part

32:非反射部 32:Non-reflective part

40X:位置資料 40X: Location data

Claims (8)

一種絕對編碼器，係具備有： 圓板狀的標度尺，係配置有絕對值碼圖案； 第一發光元件，係照射光至與前述標度尺的中心相距第一距離的第一位置； 第二發光元件，係照射光至與前述標度尺的中心相距第二距離的第二位置； 第一影像感測器，係接收來自前述第一位置之第一光而輸出與前述第一光對應的第一類比訊號； 第二影像感測器，係接收來自前述第二位置之第二光而輸出與前述第二光對應的第二類比訊號； 第一訊號轉換部，係將前述第一類比訊號轉換為第一數位訊號； 第二訊號轉換部，係將前述第二類比訊號轉換為第二數位訊號；以及 絕對位置演算部，係根據前述第一數位訊號及前述第二數位訊號而算出在前述標度尺上的第一絕對位置， 前述絕對位置演算部係根據前述第一數位訊號及前述第二數位訊號，而判定前述第一影像感測器的第一角度檢測功能及前述第二影像感測器的第二角度檢測功能是否異常，若前述第一角度檢測功能及前述第二角度檢測功能正常，就算出前述第一數位訊號所對應之在前述標度尺上的第二絕對位置與前述第二數位訊號所對應之在前述標度尺上的第三絕對位置的平均位置來作為前述第一絕對位置。 An absolute encoder with: The disc-shaped scale is equipped with an absolute value code pattern; The first light-emitting element irradiates light to a first position that is a first distance away from the center of the aforementioned scale; The second light-emitting element irradiates light to a second position that is a second distance away from the center of the aforementioned scale; The first image sensor receives the first light from the first position and outputs a first analog signal corresponding to the first light; The second image sensor receives the second light from the second position and outputs a second analog signal corresponding to the second light; The first signal conversion part converts the aforementioned first analog signal into a first digital signal; The second signal conversion part converts the aforementioned second analog signal into a second digital signal; and The absolute position calculation unit calculates the first absolute position on the scale based on the first digital signal and the second digital signal, The aforementioned absolute position calculation unit determines whether the first angle detection function of the aforementioned first image sensor and the second angle detection function of the aforementioned second image sensor are abnormal based on the aforementioned first digital signal and the aforementioned second digital signal. , if the aforementioned first angle detection function and the aforementioned second angle detection function are normal, the second absolute position corresponding to the aforementioned first digital signal on the aforementioned scale and the aforementioned second absolute position corresponding to the aforementioned second digital signal on the aforementioned scale can be calculated. The average position of the third absolute position on the scale is used as the aforementioned first absolute position. 如請求項1所述之絕對編碼器，其中， 前述絕對位置演算部係在前述第一角度檢測功能為正常且前述第二角度檢測功能為異常時，算出前述第二絕對位置來作為前述第一絕對位置， 前述絕對位置演算部係在前述第一角度檢測功能為異常且前述第二角度檢測功能為正常時，算出前述第三絕對位置來作為前述第一絕對位置。 An absolute encoder as described in claim 1, wherein, The absolute position calculation unit calculates the second absolute position as the first absolute position when the first angle detection function is normal and the second angle detection function is abnormal, The absolute position calculation unit calculates the third absolute position as the first absolute position when the first angle detection function is abnormal and the second angle detection function is normal. 如請求項1所述之絕對編碼器，其中， 前述絕對位置演算部係在前述第一角度檢測功能及前述第二角度檢測功能都異常時，使前述標度尺的旋轉停止。 An absolute encoder as described in claim 1, wherein, The absolute position calculation unit stops the rotation of the scale when both the first angle detection function and the second angle detection function are abnormal. 如請求項1至3中任一項所述之絕對編碼器，其中， 前述絕對位置演算部係在前述第一絕對位置與前述第二絕對位置的差分為基準值以上時，判定為前述第一角度檢測功能及前述第二角度檢測功能的至少其中一方為異常，並使前述標度尺的旋轉停止。 The absolute encoder as described in any one of claims 1 to 3, wherein, When the difference between the first absolute position and the second absolute position is greater than or equal to a reference value, the absolute position calculation unit determines that at least one of the first angle detection function and the second angle detection function is abnormal, and causes the The rotation of the aforementioned scale stops. 如請求項1至3中任一項所述之絕對編碼器，其中， 前述絕對位置演算部係檢測出屬於前述第一數位訊號的上升或下降的位置且為前述第一數位訊號之有無的交界之第一邊緣位置，且在前述第一邊緣位置的個數為基準值以下時判定為前述第一角度檢測功能異常， 前述絕對位置演算部係檢測出屬於前述第二數位訊號的上升或下降的位置且為前述第二數位訊號之有無的交界之第二邊緣位置，且在前述第二邊緣位置的個數為前述基準值以下時判定為前述第二角度檢測功能異常。 The absolute encoder as described in any one of claims 1 to 3, wherein, The absolute position calculation unit detects a first edge position that is a rising or falling position of the first digital signal and is a boundary between the presence or absence of the first digital signal, and the number at the first edge position is a reference value. It is determined that the aforementioned first angle detection function is abnormal when: The absolute position calculation unit detects a second edge position that is a rising or falling position of the second digital signal and is a boundary between the presence or absence of the second digital signal, and the number of the second edge positions is the reference If the value is below the value, it is determined that the second angle detection function is abnormal. 如請求項1至3中任一項所述之絕對編碼器，其中， 前述絕對位置演算部係產生與前述第一數位訊號對應的第一位元列，並產生與前述第二數位訊號對應的第二位元列， 前述絕對位置演算部係在前述第一位元列與第三位元列的差異位元數為閾值以上之情況，判定為前述第一角度檢測功能為異常，其中前述第三位元列為表示前述絕對值碼圖案的位元列之查找表內的位元列， 前述絕對位置演算部係在前述第二位元列與前述第三位元列的差異位元數為前述閾值以上之情況，判定為前述第二角度檢測功能為異常。 The absolute encoder as described in any one of claims 1 to 3, wherein, The aforementioned absolute position calculation unit generates a first bit sequence corresponding to the aforementioned first digital signal, and generates a second bit sequence corresponding to the aforementioned second digital signal, The above-mentioned absolute position calculation unit determines that the above-mentioned first angle detection function is abnormal when the number of difference bits between the above-mentioned first bit sequence and the above-mentioned third bit sequence is more than a threshold, wherein the above-mentioned third bit sequence indicates The bit sequence in the lookup table of the bit sequence of the aforementioned absolute value code pattern, The absolute position calculation unit determines that the second angle detection function is abnormal when the number of bits difference between the second bit sequence and the third bit sequence is equal to or greater than the threshold value. 如請求項1所述之絕對編碼器，其中， 前述第一影像感測器及前述第二影像感測器係配置於在從前述標度尺的旋轉軸方向觀看時隔著前述標度尺的中心而相對向的位置。 An absolute encoder as described in claim 1, wherein, The first image sensor and the second image sensor are arranged at positions facing each other across the center of the scale when viewed from the direction of the rotation axis of the scale. 如請求項1所述之絕對編碼器，其中， 前述第一發光元件及前述第二發光元件的至少其中一方與前述第一影像感測器及前述第二影像感測器的至少其中一方係安裝於一個模組。 An absolute encoder as described in claim 1, wherein, At least one of the first light-emitting element and the second light-emitting element and at least one of the first image sensor and the second image sensor are installed in a module.
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