1220688 玖、發明說明： 【發明所屬之技術領域】 β 本發明係關於一種反射式光柵量測旋轉軸誤差之裝置與 二 方法，特別是指一種反射式光柵利用光的繞射現象產生繞射光二 以量測旋轉軸偏擺誤差之裝置與方法。 ·· 【先前技術】 近年來隨工具機、各種產業機械、量測儀器的高精度化， 加上超精密加工機、半導體製程裝置、電子資訊機器、原子力籲 顯微鏡等的需要高精密定位技術儀器的發展，不論是在精密機 械、半導體產業、微（奈）米科技皆朝微小化、精密化與奈米 級的方向前進，因此在精密機械領域之量測設備、製造技術、 整合技術的發展，微奈米定位平台與精密定位檢測技術的相關 研究是不容克緩。 而在檢測旋轉軸量測儀器上，大部分的量測儀器如量錶、 LVDT、渦電流探頭，反電容式位移計等，為接觸式量測，對待籲 測物產生較大的干擾，因此誤差多較不精確，而非接觸的儀器 如雷射干涉儀、三角雷射等，又需多組探頭量測才可量出旋轉 軸的旋轉位置和傾斜角度，不能使用較簡單的架構來量測旋轉 軸，而且多組設備誤差就越多，成本越高，而且使用上述儀器一 一定要先校正圓棒（球）之配合使用，而這些校準圓棒（球）之不 確定度（Uncertainty)有一定的極限而且難以持續保養，有鑑 於此，若能發展一套較少設備、低成本高精密多自由度旋轉軸 6 122〇688 里測系統，有助於精密量測之發展。 目刖市面上可進行真圓度線上量測之裝置，其實顯示的量 測值不過是偏心度而已；例如傳統的直徑法、半徑法、三點法·. 等里測方式，皆過於簡略且有誤差產生。所謂直徑法即通常使 用/刀釐卡或缸徑規等測量數點直徑，由最大徑與最小徑之差 值’為其真圓度，由於取點數一般有其限制，僅適用於橢圓形 或偶數凸形工件之量測。所謂半徑法即通常用來量測工件半徑 外形尺寸的變化量，-般可以制Dia gauge (圓盤指示錶) 來擔任這項工作，將待測卫件安置于具有頂心裝置的檢查台 上，此檢查台提供了 一個基準轴線，故我們可將工件架於此轴 線上作旋轉，待測卫件旋轉—周後，觀察量錶指針上下移動量， 、八值的變化里，此法未考慮檢查台旋轉中心不在待測工件 ^ 目此偏心$未作補償。所謂三點法與半徑法相似，但 員#置的檢查台改為v形钻塊，此法未考慮形狀 不均勾分佈之凸形工件之量測，因此誤差甚大。 、習用-種使用雷射二極體及四象儀檢測旋轉軸誤差之方 、係如我國公告第517150號專利案（下稱引證案），其主要 構成特徵為·係將雷射光源放置在任何旋轉軸上主 轉軸决差，其特徵：將雷射二極體嵌入旋轉 四象儀放置於相斜从口 〒而 、子的另一端平台上，亦或顛倒；而其構成 主要缺點為：⑴架設量測系統甚為耗時，(2)需要夕個 而要多個渦電流 7 探頭’（3)渴電流單價纟高，使之在接收的系統上要付出不少 的成本，（4)只能夠量測到旋轉軸的χ方向及γ方向的誤差， (5)該渦電流探頭必須要架設在工具機旋轉軸的兩旁，於架設 時需非常接近旋轉軸，當旋轉軸在高速轉動的時候，若有產生 很大的偏心，極有可能會損壞到渦電流探頭。 由此可見，上述習用物品仍有諸多缺失，實非一良善之設 叶者，而亟待加以改良。 本案發明人鑑於上述習用量測旋轉軸誤差之裝置所衍生的 各項缺點，乃亟思加以改良創新，並經多年苦心孤詣潛心研究 後，終於成功研發完成本件一種反射式光栅量測旋轉軸誤差之 裝置與方法。 【發明目的】 本發明之目的即在於提供一種反射式光柵量測旋轉軸誤差 之裝置與方法，係以簡易的架設方式，來達到量測旋轉軸誤差 的大小，並且具有可量測多自由度之一裝置。 本發明之次一目的係在於提供一種反射式光柵量測旋轉軸 誤差之裝置與方法，本發明的夾置具僅須將量測光源架設在旋 轉轴’就算旋轉軸的偏心量再大，也不回損害任何量測裝置， 透過懸空在光柵兩端的四象儀去接收即可達到量測多自由度 的裝置。 本發明之另一目的係在於提供一種可採可見光、微波、紅 1220688 外光、紫外光以及X射線皆可做為量測光源’使之運用於絕對 距離量測之裝置。 【實施方式】 可達成上述發明目的之一種反射式光柵量測旋轉軸誤差之 裝置與方法，包括有： 一雷射二極體，係提供雷射光束入射至後述之反射式光柵； 一反射式光柵，係爲接收雷射光束後，使該光束能穿透光 栅以產生正負η階的繞射光，其中入射光與正n階繞射光的夾 角為0 1，與負η階繞射光的夾角為0 2 ; 一雷射四象儀a，係接收正η階繞射光的位置變化，並根 據光點入射在四象儀a上的座標位置，以改變雷射四象儀a其 輸出的電壓；以及 一雷射四象儀b，係接收負η階繞射光的位置變化，並根 據光點入射在四象儀b上的座標位置，以改變雷射四象儀b其 輸出的電壓。 【實施方式】 「請參閱圖八」，本發明所提供之一種反射式光柵量測旋轉 軸誤差之裝置與方法，主要包括有：一雷射二極體u、一反射 式光柵12、一雷射四象儀a以及一雷射四象儀b。 為更詳盡說明本發明「請再參閱圖八、九」為本發明穿透 式光柵里測系統之架構圖，本發明係主要利用一雷射二極體丄i 9 1220688 之雷射光束或可見光、微波、紅外光、紫外光及χ射線入射至 反射式光栅12，该雷射二極體11係透過夾置具架設在工具機 的旋轉軸21上，當工具機的旋轉軸21在旋轉的時候，雷射二 極體11跟著工具機的旋轉軸21旋轉，而雷射二極體11發出 的光束可為單頻雷射光、雙頻雷射光及線性調頻半導體雷射 光’當入射光入射在移動平台上的反射式光柵12後，反射式 光柵12除了會將光反射回去以外，還會產生正負^階的繞射 光，其中入射光與正η階繞射光的夾角為<9 1，而與負^階繞 射光的夾角為（92，其兩夾角角度均為相同，即01=02。在產 生正一階繞射光與負一階繞射光處，均放置一雷射四象儀a 13 與一雷射四象儀bl4，使該雷射四象儀al3能接收由反射式光 栅12所產生的正一階繞射光，該雷射四象儀bi 4接收由反射 式光柵12所產生的負一階繞射光，而雷射四象儀ai 3，bl 4會 根據光點入射於雷射四象儀a 13，b 14上的座標位置，而改變 其輸出的電壓，再由類比/數位轉換卡（A/D卡）去將這些電壓 的值讀到電腦當中，由電腦去分析，計算旋轉軸21的誤差。 由電腦去分析的時候，可以判讀由類比/數位轉換卡（A/D 卡）抓進來的值，因一個雷射四象儀al3與雷射四象儀bl4各 有一對X、Y軸。因此在分析χ、Y軸的時候，可以相互比較正 一階繞射光與負一階繞射光入射於雷射四象儀al 3與雷射四象 儀bl4的值。 10 1220688 當電腦在分析從類比/數位轉換卡（A/D卡）讀取進來的 值，正一階繞射光所打到的雷射四象儀al 3與負一階繞射光所 打到的雷射四象儀bl4,均會入射在雷射四象儀al3, bl4各X、 Y的落點上，並在雷射四象儀al3, bl4所接受的範圍内，本發 明係將旋轉軸21旋轉時所量測的值跟旋轉軸21未產生偏差的 值相比較所得之一計算旋轉軸21誤差。 「請參閱圖一」為本發明於旋轉軸未發生任何誤差之立體 示意圖，本發明可以將雷射四象儀al3與雷射四象儀bl4透過· 類比/數位轉換卡（A/D卡）將雷射四象儀上的座標點繪出，由座 標上偏移的量，來觀查誤差的值，如圖一（a)、圖一（b)所示； 當旋轉軸21在旋轉時，若發生了位移誤差，如圖二、圖四所 示’本發明架設在反射式光柵12兩端接收其繞射光的雷射四 象儀al3與雷射四象儀bl4於訊號接收進來後，其讀值會有變 化如圖二（a)、圖二（b)、圖四（a)及圖四（b)所示。 「睛再參閱圖八、九」當入射光入射在移動平台上的反射馨 式光柵12後，由反射式光柵12所產生的繞射光入射在雷射四 象儀al3與雷射四象儀bl4後，該雷射四象儀ai3與雷射四象 儀b 14上的測量值與主軸未產生偏差的值相差不大時，則代表 旋轉軸21發生了位移偏差（、5y)。若雷射四象儀上的兩個 .. 測量值與主轴未產生偏差的值相差很大時，則代表旋轉軸21 / 發生了搖擺誤差（εχ、ey)，或者是發生了位移誤差（5χ、- 11 1220688 以及搖擺誤差（εχ、ey)。 當旋轉軸21在旋轉時，若發生了搖擺誤差，如圖三、圖五 所示’本發明架設於反射式光栅12兩端用以接收其繞射光的 雷射四象儀al3與雷射四象儀M4會將訊號接收進來，接收進 來的讀值訊號會有座標位置上的變化，如圖三（3)、圖三（b)、 圖五（a)及圖五（b)所示。由前述所知，本發明可以將雷射四象 儀al3與雷射四象儀M4透過類比/數位轉換卡（A/D卡）將雷射 四象儀上的座標點繪出，由座標上偏移的量，來觀查旋轉軸21 誤差的值。 「請參閱圖六」，其顯示本發明反射式光柵12量測旋 轉軸21之誤差量測流程圖。 步驟1 :先將旋轉軸21校正到對準中心，並將雷射四象儀al3 與雷射四象儀bl4放置在光源下，以記錄雷射四象儀 al3與雷射四象儀bl4連接到類比/數位轉換卡（A/D 卡）的頃值’如圖一所示； 步驟2 ··旋轉轴21單一對X軸方向位移量偏心，記錄雷射四象 儀al3與雷射四象儀bi4連接到類比/數位轉換卡（A/I) 卡）的讀值。將「步驟丨」與「步驟2」這兩筆資料做 比敉’可以推算得到旋轉軸21對X軸方向的位移誤差 5 X，如圖四所示； 步驟3 :旋轉軸21單一對γ軸方向位移量偏心，記錄雷射四象 12 1220688 儀al3與雷射四象儀bl4連接到類比/數位轉換卡（A/D 卡）的讀值。將「步驟1」與「步驟3」這兩筆資料做 比較，可以推算得到旋轉軸21對Y軸方向的位移誤差 、 5y，如圖二所示； 步驟4 :旋轉軸21同時對X軸方向、γ軸方向位移量偏心，記 錄雷射四象儀a 13與雷射四象儀b 14連接到類比/數位 轉換卡（A/D卡）的讀值。將「步驟1」與「步驟4」這 兩筆資料做比較，可以推算得到旋轉軸21對χ軸方向鲁 的位移誤差5 X (如圖四所示）、γ軸方向的位移誤差 (如圖二所示）；以及 步驟5 :將假設在下方的反射式光柵12做小角度的傾斜，記錄 雷射四象儀al3與雷射四象儀bl4連接到類比/數位轉 換卡（A/D卡）的讀值。將「步驟丄」與「步驟5」這兩 筆資料做比較，可以推算得到旋轉軸21對χ軸方向傾 斜的搖擺誤差ε χ (如圖五所示）、γ軸方向傾斜的搖鲁 擺^差£y (如圖三所示）。 【特點及功效】 本發明所提供之一種反射式光柵量測旋轉軸誤差之裝置與 方法，與前述引證案及其他習用技術相互比較時，更具有下列. 之優點： (1)本發明以雷射二極體搭配反射式光栅利用光波繞射原， 13 l22〇688 理，將入射光束反射回去後產生正負n階的繞射光，在產生正 一階繞射光與負一階繞射光處，均放置一雷射四象儀，利用雷 射四象儀去接收由反射式光柵所產生的繞射光，除了可量測到 · X方向及Υ方向的誤差之外，還可以量測到朝X方向及γ方向 心 的偏搖度誤差，實在可視為量測技術上的一大突破，也可較— 般量測技術還精確且更細微。 上列詳細說明係針對本發明之一可行實施例之具體說明， 惟該實施例並非用以限制本發明之專利範圍，凡未脫離本發明寒( 技藝精神所為之等效實施或變更，均應包含於本案之專利範固 中。 、·’示上所述本案不但在技術思想上確屬創新，並能較習用 物品增進上述多項功效，應已充分符合新穎性及進步性之法定 發明專利要件，爰依法提出巾請#局核准本件發明專 利申請案，以勵發明，至感德便。 【圖式簡單說明】 請參閱以下有關本發明—較佳實施例之詳細說明及其附 圖，將可進-步瞭解本發明之技術内容及其目的功效；有關該 實施例之附圖為·· 、㈢料發明—種反射式光栅量測旋轉轴誤差之裝置與方 法於旋轉軸未發生任何誤差之立體示意圖； 圖一⑷為旋轉軸未發生任何誤差於雷射四象儀接收正一 1220688 階繞射光之示意圖； 圖一（b )為旋轉轴未發生任何誤差於雷射四象儀接收負一 階繞射光之示意圖； 圖'一為本發明一種反射式光拇量測旋轉輛誤差之裝置與方 法於旋轉軸產生y軸位移誤差之立體示意圖； 圖二（a)為旋轉軸產生y軸位移誤差於雷射四象儀接收正 一階繞射光之示意圖； 圖二（b)為旋轉軸產生y軸位移誤差於雷射四象儀接收負 一階繞射光之示意圖； 圖二為本發明一種反射式光柵量測旋轉軸誤差之裝置與方 法於旋轉軸產生y軸搖擺誤差之立體示意圖； 圖三（a)為旋轉軸產生y軸搖擺誤差於雷射四象儀接收正 一階繞射光之示意圖； 圖二（b)為旋轉軸產生y軸搖擺誤差於雷射四象儀接收負 一階繞射光之示意圖； 圖四為本發明一種反射式光柵量測旋轉軸誤差之裝置與方 法於旋轉軸產生X轴位移誤差之立體示意圖； 圖四（a)為旋轉軸產生χ軸位移誤差於雷射四象儀接收正 一階繞射光之示意圖； 圖四（b )為旋轉軸產生χ軸位移誤差於雷射四象儀接收負 一階繞射光之示意圖； 1220688 圖五為本發明-種反射式光栅量測旋轉轴誤差之裝置與方 法於旋轉轴產生X軸搖擺誤差之立體示意圖； 圖五（a)為旋轉軸產生x軸搖擺誤差於雷射四象儀接收正 一階繞射光之示意圖； 圖五（b)為旋轉軸產生x軸搖擺誤差於雷射四象儀接收負 一階繞射光之示意圖； 圖六為該一種反射式光栅量測旋轉軸誤差之流程圖； 圖七為本發明於量測旋轉軸時之四個誤差示意圖裝置之視 圖；以及 圖八、九為該一種反射式光栅量測旋轉軸誤差裝置之架構 圖。 【主要部分代表符號】 11雷射二極體 12反射式光柵 13雷射四象儀a 14雷射四象儀b 21旋轉軸 占x沿著X軸向的位移誤差 5 y沿著y軸向的位移誤差 ε X沿著X軸向的搖擺誤差 ε y沿著y轴向的搖擺誤差 161220688 发明 Description of the invention: [Technical field to which the invention belongs] β The present invention relates to a reflective grating device and two methods for measuring rotation axis errors, and particularly to a reflective grating that uses diffraction of light to generate diffraction light II Device and method for measuring deviation of rotation axis. ·· [Previous technology] In recent years, with the high precision of machine tools, various industrial machinery, and measuring instruments, coupled with ultra-precision processing machines, semiconductor manufacturing equipment, electronic information equipment, and atomic force microscopes, high-precision positioning technology and equipment are required. Development in both the precision machinery, semiconductor industry, and micro (nano) technology is progressing toward miniaturization, precision, and nanometer level. Therefore, the development of measurement equipment, manufacturing technology, and integration technology in the field of precision machinery The research on the micronano positioning platform and precise positioning detection technology is not to be delayed. On the rotating shaft measuring instruments, most of the measuring instruments, such as scales, LVDTs, eddy current probes, anti-capacitive displacement meters, etc., are contact-type measurements that cause greater interference with the object being measured, so The errors are more inaccurate, and non-contact instruments such as laser interferometers and triangle lasers require multiple sets of probe measurements to measure the rotation position and tilt angle of the rotation axis. A simpler structure cannot be used to measure Measuring the rotation axis, and the more errors of multiple sets of equipment, the higher the cost, and the use of the above-mentioned instruments must first be used in conjunction with the calibration of round rods (balls), and the uncertainty of these calibration round rods (balls) (Uncertainty ) Has a certain limit and it is difficult to maintain it continuously. In view of this, if a set of less equipment, low-cost, high-precision multi-degree-of-freedom rotating shaft 6 122〇688 in-line measurement system can be developed, it will help the development of precision measurement. The devices on the market that can be used to measure true roundness on the market, in fact, the measured values displayed are only eccentricity; for example, the traditional diameter method, radius method, three-point method, etc., the internal measurement methods are too simple and There is an error. The so-called diameter method is generally used to measure the diameter of several points, such as / Centimeter or cylinder gauge, the difference between the maximum diameter and the minimum diameter 'is its roundness. Since the number of points is generally limited, it is only applicable to oval or Measurement of even-numbered convex workpieces. The so-called radius method is usually used to measure the change in the radius and shape of the workpiece. Generally, a Dia gauge (disk indicator) can be used to do this work. The guard to be tested is placed on an inspection table with a top-center device. This inspection table provides a reference axis, so we can rotate the workpiece on this axis, and the guard to be tested rotates-after a week, observe the amount of movement of the pointer of the gauge up and down. The rotation center of the inspection table is not considered. The eccentricity $ is not compensated. The so-called three-point method is similar to the radius method, but the inspection table set by the member # is changed to a V-shaped drill block. This method does not consider the measurement of convex workpieces with uneven shapes, so the error is very large. Conventional-a method of detecting the error of the rotation axis using a laser diode and a four-camera instrument, such as the Chinese Patent No. 517150 (hereinafter referred to as the "citation case"), its main constituent features are: the laser light source is placed in The main rotation axis on any rotation axis is absolutely different. Its characteristics are as follows: the laser diode is embedded in the rotating four imager and placed on the other side of the platform, or the other side is inverted; and its main disadvantages are: ⑴ Setting up a measurement system is very time consuming, (2) multiple eddy current 7 probes are needed, and (3) the unit price of thirsty current is so high that it will pay a lot of cost on the receiving system, (4 ) Only the errors in the χ and γ directions of the rotation axis can be measured. (5) The eddy current probe must be erected on both sides of the rotation axis of the machine tool. When it is set up, it must be very close to the rotation axis. When the rotation axis is rotating at high speed If there is a large eccentricity, the eddy current probe may be damaged. It can be seen that there are still many shortcomings in the above-mentioned conventional articles, and they are not a good leaf-setter, but need to be improved. In view of the various shortcomings derived from the above-mentioned device for measuring the rotation axis error, the inventor of this case has been eager to improve and innovate. After years of painstaking and meticulous research, he has finally successfully developed a reflective grating to measure the rotation axis error. Device and method. [Objective of the Invention] The purpose of the present invention is to provide a device and method for measuring the rotation axis error using a reflective grating. The method is simple to set up to measure the size of the rotation axis error and has multiple degrees of freedom that can be measured. One device. A second object of the present invention is to provide a reflective grating device and method for measuring the rotation axis error. The clamping device of the present invention only needs to mount the measurement light source on the rotation axis. Even if the eccentricity of the rotation axis is large, Without damaging any measurement device, a device with multiple degrees of freedom can be measured by receiving through a four-image instrument suspended at both ends of the grating. Another object of the present invention is to provide a device that can use visible light, microwaves, red 1220688 external light, ultraviolet light, and X-rays as measurement light sources, and use it for absolute distance measurement. [Embodiment] A reflective grating device and method for measuring the rotation axis error that can achieve the above-mentioned object of the invention includes: a laser diode, which provides a laser beam incident on a reflective grating described later; a reflective type Grating is to receive the laser beam, so that the beam can penetrate the grating to produce positive and negative η-order diffraction light. The angle between the incident light and the positive n-order diffraction light is 0 1 and the angle between the incident light and the negative η-order diffraction light is 0 2; a laser four-imager a, which changes the position of receiving positive η-order diffracted light, and changes the output voltage of the laser four-imager a according to the coordinate position of the light spot incident on the four-imager a; And a laser four-imager b, which changes the position of receiving negative η-order diffracted light, and changes the output voltage of the laser four-imager b according to the coordinate position where the light spot is incident on the four-imager b. [Embodiment] "Please refer to Fig. 8", a reflective grating device and method for measuring rotation axis error provided by the present invention mainly includes: a laser diode u, a reflective grating 12, and a lightning A four-camera a and a four-camera b. For a more detailed explanation of the present invention "please refer to Figs. 8 and 9 again", the structure diagram of the penetrating grating in-measurement system of the present invention. The present invention mainly uses a laser beam of a laser diode 丄 i 9 1220688 or visible light. , Microwave, infrared light, ultraviolet light and X-ray are incident on the reflective grating 12, the laser diode 11 is mounted on the rotating shaft 21 of the machine tool through a clamping tool. When the rotating shaft 21 of the machine tool is rotating, At this time, the laser diode 11 rotates with the rotary axis 21 of the machine tool, and the beam emitted by the laser diode 11 can be a single-frequency laser light, a dual-frequency laser light, and a chirp semiconductor laser light. After moving the reflective grating 12 on the platform, in addition to reflecting the light back, the reflective grating 12 will also generate positive and negative ^ order diffraction light, where the angle between the incident light and the positive η order diffraction light is < 9 1 and The included angle with the negative ^ -order diffraction light is (92, and the two included angles are the same, that is, 01 = 02. Where a positive first-order diffraction light and a negative first-order diffraction light are generated, a laser four imager a 13 is placed. With a laser four imager bl4, make the laser four imager al3 Receiving the positive first-order diffracted light generated by the reflective grating 12, the laser four-imager bi 4 receives the negative first-order diffracted light generated by the reflective grating 12, and the laser four-imager ai 3, bl 4 will According to the coordinates of the light spot incident on the four laser imagers a 13, b 14, the output voltage is changed, and the analog / digital conversion card (A / D card) is used to read these voltage values into the computer The computer analyzes it and calculates the error of the rotation axis 21. When the computer analyzes it, it can judge the value captured by the analog / digital conversion card (A / D card), because a laser four-imager al3 and laser The four imagers bl4 each have a pair of X and Y axes. Therefore, when analyzing the χ and Y axes, it is possible to compare the positive first order diffraction light and the negative first order diffraction light to the laser four imager al 3 and the laser four imager. The value of the instrument bl4. 10 1220688 When the computer is analyzing the value read from the analog / digital conversion card (A / D card), the laser four-imager al 3 hit by the positive first-order diffraction light and the negative first-order diffraction The four laser imagers bl4 hit by the light will be incident on the X, Y landing points of the four laser imagers al3, bl4, and the laser Within the range accepted by the four imagers al3, bl4, the present invention calculates the error of the rotating shaft 21 by comparing one of the value measured when the rotating shaft 21 rotates with a value that does not produce a deviation of the rotating shaft 21. "Please refer to the figure "One" is a three-dimensional schematic diagram of the present invention without any error on the rotation axis. The present invention can pass the laser four imager al3 and the laser four imager bl4 through the analog / digital conversion card (A / D card) to convert the laser four The coordinate points on the imager are plotted, and the amount of deviation is used to observe the value of the error, as shown in Figure 1 (a) and Figure 1 (b). When the rotation axis 21 is rotating, if The displacement error is shown in Figures 2 and 4. 'The present invention sets up the laser four-imager al3 and laser four-imager bl4 which receive the diffracted light at both ends of the reflective grating 12 after the signal is received. The changes are shown in Figure 2 (a), Figure 2 (b), Figure 4 (a) and Figure 4 (b). "Eye again refer to Figures 8 and 9" After the incident light is incident on the reflective grating 12 on the mobile platform, the diffracted light generated by the reflective grating 12 is incident on the four laser imager al3 and the four laser imager bl4 Later, when the measured values on the four laser imager ai3 and the four laser imager b 14 are not significantly different from the value of the main shaft without deviation, it means that the displacement deviation (, 5y) of the rotation axis 21 has occurred. If two .. on the laser four imager. The measured value and the value of the main axis do not deviate greatly, it means that the rotation axis 21 / rocking error (εχ, ey) occurred, or a displacement error (5χ ,-11 1220688, and sway error (εχ, ey). When the sway error occurs when the rotating shaft 21 is rotating, as shown in Figs. 3 and 5, the present invention is erected at both ends of the reflective grating 12 to receive it. The four laser imager al3 and the four laser imager M4 with diffracted light will receive the signal, and the reading signal received will change the position of the coordinates, as shown in Figure 3 (3), Figure 3 (b), and Figure 3. As shown in Figure 5 (a) and Figure 5 (b), from the foregoing, the present invention can convert the laser four-imager al3 and the laser four-imager M4 through the analog / digital conversion card (A / D card) to the laser. The coordinate points on the four-image instrument are drawn, and the deviation of the coordinates is used to observe the error value of the rotation axis 21. "Please refer to Figure 6", which shows the error of the rotation axis 21 measured by the reflective grating 12 of the present invention. Measurement flow chart Step 1: First align the rotation axis 21 to the alignment center, and set the four laser imager al3 and the four laser imager The instrument bl4 is placed under the light source to record the value of the laser four imager al3 and the laser four imager bl4 connected to the analog / digital conversion card (A / D card) as shown in Figure 1. Step 2 ·· Rotate The axis 21 is eccentric to the displacement in the X-axis direction, and records the readings of the laser four imager al3 and the laser four imager bi4 connected to the analog / digital conversion card (A / I) card. Comparing the two pieces of data of "Step 丨" and "Step2", the displacement error 5 X of the rotation axis 21 in the X-axis direction can be calculated, as shown in Fig. 4; Step 3: A single rotation axis 21 pairs the γ axis The direction displacement is eccentric. Record the readings of the laser four image 12 1220688 instrument al3 and the laser four image instrument bl4 connected to the analog / digital conversion card (A / D card). Comparing the two data of "Step 1" and "Step 3", the displacement error of the rotation axis 21 in the Y-axis direction, 5y can be calculated, as shown in Figure 2. Step 4: The rotation axis 21 is simultaneously in the X-axis direction The displacement amount in the direction of γ axis is eccentric. Record the readings of the laser four imager a 13 and the laser four imager b 14 connected to the analog / digital conversion card (A / D card). Comparing the two data of "Step 1" and "Step 4", the displacement error 5 X of the rotation axis 21 in the χ-axis direction can be calculated (as shown in Figure 4), and the displacement error in the γ-axis direction (as shown in Figure 4). 2); and Step 5: Suppose the reflective grating 12 below is tilted at a small angle, and record the laser four imager al3 and the laser four imager bl4 to the analog / digital conversion card (A / D card ). Comparing the two data of "step 丄" and "step 5", we can calculate the swing error ε χ of the rotation axis 21 tilted in the χ-axis direction (as shown in Figure 5), and the swing pendulum tilted in the γ-axis direction ^ £ y (as shown in Figure 3). [Features and effects] The device and method for measuring the rotation axis error provided by the reflective grating provided by the present invention have the following advantages when compared with the aforementioned citations and other conventional techniques: (1) The present invention uses thunder The radiating diode is combined with a reflective grating to utilize the diffraction principle of light waves. The 131222688 mechanism reflects the incident beam back to produce positive and negative n-order diffracted light. Both positive and negative first-order diffracted light and negative first-order diffracted light are generated. Place a laser four imager and use the laser four imager to receive the diffracted light generated by the reflective grating. In addition to measuring the errors in the · X and Υ directions, you can also measure in the X direction. And the yaw error of the γ direction center can be regarded as a breakthrough in measurement technology, and it can also be more accurate and more detailed than the general measurement technology. The above detailed description is a specific description of a feasible embodiment of the present invention, but this embodiment is not intended to limit the patent scope of the present invention. Any equivalent implementation or change that does not depart from the spirit of the present invention It is included in the patent scope of this case. The above-mentioned case is not only technically innovative, but also can enhance the above-mentioned multiple effects compared with conventional items. It should have fully met the requirements for novel and progressive legal invention patents. According to the law, please submit the application to #Office for approval of this invention patent application, in order to stimulate the invention, to the best of your abilities. [Brief description of the drawings] Please refer to the following detailed description of the present invention-preferred embodiment and the accompanying drawings. You can further understand the technical content of the present invention and its purpose and effectiveness; the drawings related to this embodiment are: ··· ㈢ 料 invention-a reflection grating device and method for measuring the rotation axis error without any error on the rotation axis Schematic diagram of the perspective; Figure 1 is a schematic diagram of the receiving of the positive 1220688 order diffracted light in the laser four imager without any error; Figure 1 (b) is the rotation axis Schematic diagram of the laser four imager receiving negative first-order diffracted light; Figure 'a is a three-dimensional schematic diagram of the y-axis displacement error generated on the rotation axis by a reflective light thumb measuring device and method of the invention; Figure 2 (a) is a schematic diagram of the y-axis displacement error generated by the rotation axis when the laser four imager receives positive first order diffraction light; Figure 2 (b) is the y-axis displacement error of the rotation axis generated when the laser four imager receives negative one Schematic diagram of the second-order diffraction light; Figure 2 is a three-dimensional schematic diagram of a reflective grating device and method for measuring the rotation axis error of the present invention that generates a y-axis wobble error on the rotation axis; Schematic diagram of a laser four imager receiving positive first-order diffracted light; Figure 2 (b) is a schematic diagram of a rotary axis generating a y-axis swing error; The device and method for measuring the rotation axis error by a grating are three-dimensional schematic diagrams of the X-axis displacement error generated on the rotation axis; Figure 4 (a) is a schematic diagram of the x-axis displacement error generated by the rotation axis and received by a laser four imager with positive first-order diffraction light. Figure 4 (b) is a schematic diagram of the x-axis displacement error generated by the rotation axis in the laser four imager receiving negative first-order diffracted light; 1220688 Figure 5 is a device and method for measuring the rotation axis error of a reflective grating of the present invention Figure 3 (a) is a schematic diagram of the x-axis wobble error generated by the rotation axis; Figure 5 (b) is a schematic diagram of the laser four imager receiving positive first-order diffraction light; Figure 5 (b) is the x-axis wobble generated by the rotation axis. Schematic diagram of error receiving negative first order diffracted light by laser imager; Figure 6 is a flowchart of measuring the rotation axis error of a reflective grating; Figure 7 is a schematic diagram of the four errors of the invention when measuring the rotation axis Figures 8 and 9 are the structural diagrams of this kind of reflective grating measuring device for measuring the rotation axis error. [Representative symbols of main parts] 11 laser diode 12 reflective grating 13 laser four imager a 14 laser Four-imager b 21 Rotational axis accounts for the displacement error along the x-axis x 5 y The displacement error along the y-axis ε The swing error along the x-axis ε The swing error along the y-axis 16