200842312 九、發明說明： 【舍明所屬之技術領域】 本發明係關於—# μ + ^ & 係關於一種可作為線焦:頭光學尺’詳言之 測精密機台的移動量者/里測之I測系統’以有效地i 【先前技術】 光學尺係可用來量測精密機台的_200842312 IX. Description of the invention: [Technical field to which Sheming belongs] The present invention relates to -# μ + ^ &; relates to a type of movement that can be used as a line focus: head optical ruler's detailed measurement machine Measuring the I test system 'to effectively i 【Previous technology】 Optical ruler can be used to measure precision machine _
不，其主要元件包含有—主光栅⑴、1光 ^圖戶 :蝴:組⑺，其主光栅⑴與副光柵(彳;: 隔之平行格子（11)、（21)，較長 ^目田夕^ ⑴’另外-片則可移動稱為副光栅(2)，該光學 理，係透過發光二極體(4)產生光源經聚光透鏡⑷)投= 主光栅（1)與副光柵(2)，副光栅(2)與發光二極體(4)、 透鏡⑼、光檢測模組(3)同步移動，當副光树⑺沿著^ 柵⑴移動時，藉由光檢測模組(3)檢測穿透主光拇⑴盘畐 光柵(2)之光源’以獲得-組正交的弦波訊號，繼而利用, 號四分割與細分魏理，計算㈣錢台之移動方向㈣ 動量。 隨著高科技產業的快速發展，微奈米級的定位系統需 求量日增，對於光學尺的精度要求也相對地提高，因此採 用繞射干涉方式的光學尺專利相繼地被發表，儘管有相當 多的專利發表，然由於組成光學尺之光學元件、光檢測器… 等對位不良問題，使所得的正交訊號存在著訊號直流準位 偏移、振幅不同及相對相位偏移等訊號不完美問題，而造 5 200842312 成量測的誤差。 【發明内容】 爰此，本發明之主要目的在於提供一種雙雷射聚焦讀 頭光學尺，其係在於基座上分別固定有旋轉調整裝置、物 鏡、第二分光鏡及反射鏡，該旋轉調整裝置係設有雷射輸 出與訊號接收裝置，而該第二分光鏡設有物鏡，該第一雷 射聚焦讀頭包括一雷射輸出與訊號接收裝置、一第二分光 鏡、一物鏡，該第二雷射聚焦讀頭包括一雷射輸出與訊號 ® 接收裝置、一反射鏡、一第二分光鏡、一物鏡，又第一雷 射聚焦讀頭與第二雷射聚焦讀頭共用一第二分光鏡與一物 • 鏡；利用旋轉調整裝置調整雷射輸出與訊號接收裝置，使 ' 經由物鏡聚焦的兩聚焦光點距離相等於四分之一光柵尺間 距，當光柵尺隨著精密機台移動時，可直接量測光柵尺的 表面輪廓變化，以獲得一組正交的弦波訊號，繼而利用訊 號四分割與細分割處理，計算出精密機台之移動方向與移No, its main components include - main grating (1), 1 light ^ map household: butterfly: group (7), its main grating (1) and sub-grating (彳;: parallel grid (11), (21), longer Tian Xi ^ (1) 'Additional - sheet is movable as sub-grating (2), the optical principle is generated by the light-emitting diode (4) through the collecting lens (4)) = main grating (1) and sub-grating (2) The sub-grating (2) moves synchronously with the light-emitting diode (4), the lens (9), and the light detecting module (3), and when the sub-light tree (7) moves along the gate (1), the light detecting module (3) Detecting the light source 'passing the main light (1) disk grating (2) to obtain a group of orthogonal sine wave signals, and then using the number four division and subdivision Wei Li, calculating (four) the movement direction of the money station (four) momentum . With the rapid development of the high-tech industry, the demand for micro-nano-level positioning systems is increasing, and the accuracy requirements for optical tapes are relatively increased. Therefore, patents for optical tapes using diffraction interference have been published one after another, although quite Many patents have been published, but due to the problem of misalignment of optical components, photodetectors, etc., which constitute optical scales, the resulting orthogonal signals have signal DC offset offset, amplitude difference and relative phase offset. Problem, and made 5 200842312 into the measured error. SUMMARY OF THE INVENTION Accordingly, it is a primary object of the present invention to provide a dual laser focusing read head optical scale in which a rotation adjusting device, an objective lens, a second beam splitter and a mirror are respectively fixed on a base, and the rotation adjustment is performed. The device is provided with a laser output and signal receiving device, and the second beam splitter is provided with an objective lens. The first laser focusing read head comprises a laser output and signal receiving device, a second beam splitter and an objective lens. The second laser focus read head includes a laser output and signal® receiving device, a mirror, a second beam splitter, an objective lens, and the first laser focus read head and the second laser focus read head share a first a dichroic mirror and a mirror; the rotation adjustment device is used to adjust the laser output and the signal receiving device so that the distance between the two focused spots focused by the objective lens is equal to the pitch of the quarter grating, when the grating ruler follows the precision machine When the stage moves, the surface profile change of the scale can be directly measured to obtain a set of orthogonal sine wave signals, and then the signal quadruple division and fine division processing are used to calculate the moving side of the precision machine. Move to and from
本發明實施例確實具有下列之優點與特色·· 1. 本發明係利用雷射聚焦讀頭，其光學聚焦量測方式具有 極高位移解析度，且不易受到環境因素影響〔例如：容 電雜訊(triboelectric noise)、電磁干擾、濕度、溫度變化… 等〕之光學量測特性，藉以記錄出光栅尺間距與表面高 度的變化，進而得到光柵尺之移動方向與移動量，其整 體設計簡單，並且在調整上非常容易。 2. 本發明採用光學聚焦量測方式，直接量測光柵尺間距與 6 200842312 表面高度的變化，可降低因外界的振動干擾所造成的量 測誤差。 3. 本發明之旋轉調整裝置，可輕易地將兩雷射聚焦光點的 相對距離調整至四分之一光柵尺間距大小，以獲得一組 正交的弦波訊號，由於兩雷射聚焦光點的相對距離固定 不變，因此由雙雷射聚焦讀頭所輸出的兩弦波訊號相位 始終相差九十度，無相對相位偏移問題。 4. 本發明採用雙雷射聚焦讀頭直接量測光栅尺間距與表 面高度的變化，量测過程是沿著光栅尺表面量測，由於 線性光柵尺具有刻度的表面相當平直，因此由雙雷射聚 焦讀頭所輸出的訊號除弦波訊號外，無直流準位偏移問 題0The embodiment of the invention has the following advantages and features: 1. The invention utilizes a laser focusing read head, and the optical focusing measurement method has extremely high displacement resolution and is not easily affected by environmental factors (for example: capacitive The optical measurement characteristics of the (triboelectric noise), electromagnetic interference, humidity, temperature change, etc., in order to record the variation of the grating pitch and the surface height, thereby obtaining the moving direction and the moving amount of the grating ruler, and the overall design is simple. And it is very easy to adjust. 2. The invention adopts the optical focusing measurement method to directly measure the grating pitch and the change of the surface height of 200842312, which can reduce the measurement error caused by external vibration interference. 3. The rotation adjusting device of the present invention can easily adjust the relative distance between the two laser focusing spots to a quarter grating pitch to obtain a set of orthogonal sine wave signals, due to the two laser focused lights The relative distance of the points is fixed, so the phase of the two-string signal outputted by the double-laser focusing read head always differs by ninety degrees, and there is no relative phase shift problem. 4. The invention directly measures the variation of the grating pitch and the surface height by using a double laser focusing read head, and the measuring process is measured along the surface of the grating ruler, since the surface of the linear grating has a scale is quite straight, so The signal output by the laser focus read head has no DC level shift problem except the sine wave signal.
5. 本發明採用雙雷射聚焦讀頭直接量測光柵尺間距與表 面高度的變化，由於兩雷射聚焦讀頭皆採以相同的訊號 處理方式，直接量測光柵尺表面的輪廓變化，因此兩雷 射聚焦讀頭的弦波輸出訊號，除了相位相差九十度外， 所量測的振幅相同於光栅尺表面刻度的高度變化，因此 由雙雷射聚焦讀頭所輸出的正交弦波訊號，無振幅不同 問題。 6. 本發明係採用單一物鏡來完成兩雷射聚焦讀頭的設 計，因此可使兩雷射聚焦光點的相對距離相當接近，減 少因兩個雷射聚焦讀頭之聚焦光點距離太遠所造成的 量測誤差。 7. 本發明可經由選擇不同物鏡的數值孔徑（Numerical 2008423125. The invention directly measures the variation of the grating pitch and the surface height by using the double laser focusing read head. Since the two laser focusing reading heads adopt the same signal processing method, the contour of the surface of the grating is directly measured, so The sine wave output signal of the two laser focusing read heads, except for the phase difference of 90 degrees, the measured amplitude is the same as the height change of the scale surface scale, so the orthogonal sine wave output by the double laser focusing read head Signal, no amplitude difference. 6. The present invention uses a single objective lens to complete the design of the two laser focusing read heads, so that the relative distances of the two laser focused spotts are relatively close, reducing the distance from the focused spot of the two laser focusing read heads. The measurement error caused. 7. The present invention can select numerical apertures of different objective lenses (Numerical 200842312)
Aperture，Ν·Α·)大小，來改變兩雷射聚焦光點直徑的大 小，使雙雷射聚焦讀頭可應用於各種不同間距大小的光 柵尺，且能同樣地輸出一正交弦波訊號。 綜合以上所述優點與特色，本發明之雙雷射聚焦讀頭 光學尺，對精度日益要求的今日，實為一具實用性之發明。 為使貴審查委員對本發明裝置之内容及功用做更深 φ 一層的暸解，茲針對本發明中之圖示及符號對照列示如 後，並於實施例之詳述中配合圖示說明。 【實施方式】 、 首先，請參閱第二、三、®圖，本發明之雙雷射聚焦 讀頭光學尺，其主要由基座（5)、雷射輸出與訊號接收裝置 (6a〜6b)、第二分光鏡(7)、物鏡(8)、反射鏡(9)及光柵尺（1〇) 等構件所組成。其中，基座（5)上設有旋轉調整座 (55a〜55b)，該旋轉調整座（55a〜55b) —端則設有貫穿孔 ® (55la〜55lb)以供圓柱（56a〜56b)穿過，作為旋轉調整座 (55a〜55b)的旋轉中心，又該旋轉調整座（55a〜55b)中間則設 有弧形槽（552a〜552b)，藉以調整完畢後，供螺絲（58a〜58b) 將旋轉調整座（55a〜55b)鎖固於基座（5)之螺孔（59a〜59b) 上，又於基座（5)上設有鏡組固定座（51)，該鏡組固定座（51) 上則設有第二分光鏡(7)、物鏡(8)及反射鏡(9)。旋轉調整座 (55a〜55b)，其係用精密微調螺絲(52a〜52b)去推動，又頂針 (53a〜53b)上設有彈簧（54a〜54b)，該彈簧（54a〜54b)固定於頂 8 200842312 針座（57a〜57b)上，以提供旋轉調整座（55a〜55b)—回復彈 力，使旋轉調整座（55a〜55b)以貫穿孔(551a〜551b)為旋轉中 心，達成一個旋轉的調整裝置。 雷射輸出與訊號接收裝置（6a〜6b)，其係固定於旋轉調 整座（55a〜55b)上，如第五圖所示，該雷射輸出與訊號接收 裝置(6a)之内部係分別設有二極體雷射（61a)、第一分光鏡 (62a)、準直透鏡(63a)及四象限光感測器（64a)〔 four-quadrant photo detector〕，如第六圖所示，該雷射輸出與訊號接收裝 ® 置（61>)之内部係分別設有二極體雷射(61b)、第一分光鏡 (62b)、準直透鏡(63b)及四象限光感測器（64b)〔 four-quadrant photo detector〕。 ' 第一雷射聚焦讀頭包括有一雷射輸出與訊號接收裝 置(6a)，一第二分光鏡(7)，一物鏡(8)〔如第五圖所示〕， 投射光束係由二極體雷射(61 a)射向第一分光鏡(62a)，雷射 光束在通過第一分光鏡(62a)後，經過一準直透鏡(63a)成平 φ 行光束，再經過一第二分光鏡(7)，然後經由物鏡(8)聚焦在 光柵尺（10)上，而反射光束則循原路徑經物鏡(8)之後經第 二分光鏡(7)，再經準直透鏡(63a)與第一分光鏡(62a)後而 投射至四象限光感測器（64a)上。 第二雷射聚焦讀頭包括有一雷射輸出與訊號接收裝 置(6b)，一反射鏡(9)，一第二分光鏡(7)，一物鏡(8)〔如 第六圖所示〕，投射光束係由二極體雷射(6lb)射向第一分 光鏡(62b)，雷射光束在通過第一分光鏡(62b)後，經過一準 直透鏡(63b)成平行光束，經過反射鏡(9)將平行光束轉90 9 200842312 度，再經過—第二分光鏡(7)’然後經由物鏡(8)聚焦在光栅 尺（10)上，而反射光束則循原路徑經物鏡(8)之後經第二分 光鏡(7) ’經反射鏡(9) ’再經準直透鏡(63b)與第一分光鏡 (62b)後而投射至四象限光感測器（64b)上。 本鲞明之雷射聚焦讀頭的光學聚焦原理，係利用聚焦 董測方法中之像散法，所謂像散法是指成像時橫向與縱向 的成像位置不同，因此造成像點的失真，利用此一像散特 性做為量測的依據，所以當光柵尺⑽表面的位置在物鏡 ⑻的聚焦平面上，第-雷射聚焦讀頭之反射光經由第二分 光鏡⑺’再經準直透鏡(63a)與第—分光鏡(㈣會在四象 限光感測器（64a)上形成一個圓形區域，而第二雷射聚隹續 .頭之反射光經由第二分光鏡⑺與反射鏡⑼，再經準直透鏡 -分光樣會在四象限光感測器（64b)上 形成-個圓形區域；若光柵尺（10)表面位於物鏡⑻的非聚 焦區域’第-f㈣焦讀馳第二分麵⑺，再經準直透 #鏡_)與第-分光鏡(62a)的反射光在四象限光感測器 (64a)上形成的形狀則為橢圓形’而第二雷射聚焦讀頭則經 第二分光鏡⑺與反射鏡⑼，再經準直透鏡(㈣声第一分 t ㈣Μ # t ϋ Μ感測器（祕)上形成 的形狀則為橢圓形。 當光栅尺⑽位於如第五圖-A所示的非聚焦位置時， 則第-雷射《、讀頭經第二分光鏡(7)，再經準直透鏡 與第-分光鏡(62a)後的反射光在四象限光感測器（64a)會 形成錯直橢圓型光點，而第二雷射聚焦讀頭則經第二分光 200842312 鏡⑺與反㈣(9) ’再經準直透鏡(㈣)與第—分光鏡(6利 後的反射光同樣地在四象限光感測器（64b)會形成錯直擴 圓型光點；四象限光感測器（64a〜64b)訊號經由自製的聚焦 誤差處理電路處理後為正電壓輸出〔即四象限光感測器 (64a〜64b)之（I +ΙΠ)·〇ΐ+Ιν)為正電幻；當光栅尺⑽位於Aperture, Ν·Α·) size, to change the size of the focus of the two laser focused spots, so that the dual laser focusing read head can be applied to the grating scales of different pitch sizes, and can output a sinusoidal wave signal equally. . In combination with the above advantages and features, the dual laser focusing read head optical scale of the present invention is a practical invention for today's increasingly demanding precision. For a more detailed understanding of the contents and functions of the apparatus of the present invention, the drawings and the symbolic references in the present invention are set forth below, and are illustrated in the detailed description of the embodiments. [Embodiment] First, please refer to the second, third, and ® diagrams. The dual laser focusing read head optical scale of the present invention mainly comprises a base (5), a laser output and a signal receiving device (6a~6b). The second beam splitter (7), the objective lens (8), the mirror (9) and the grating ruler (1〇) are composed of components. Wherein, the base (5) is provided with rotation adjusting seats (55a-55b), and the rotating adjusting seats (55a-55b) are provided with through-holes (55la~55lb) for the cylinders (56a-56b) to wear. As the center of rotation of the rotation adjustment seats (55a to 55b), arc-shaped grooves (552a to 552b) are provided in the middle of the rotation adjustment seats (55a to 55b), and after the adjustment is completed, the screws (58a to 58b) are provided. The rotation adjusting seats (55a to 55b) are locked on the screw holes (59a to 59b) of the base (5), and the mirror base fixing seat (51) is further provided on the base (5). (51) The second beam splitter (7), objective lens (8) and mirror (9) are provided. The rotation adjusting seats (55a to 55b) are pushed by the fine adjustment screws (52a to 52b), and the thimbles (53a to 53b) are provided with springs (54a to 54b), and the springs (54a to 54b) are fixed to the top. 8 200842312 The needle holders (57a to 57b) are provided with rotary adjustment seats (55a to 55b) to restore the elastic force, so that the rotation adjustment seats (55a to 55b) are rotated at the through holes (551a to 551b) to achieve a rotation. Adjust the device. The laser output and signal receiving devices (6a to 6b) are fixed to the rotation adjusting seats (55a to 55b). As shown in the fifth figure, the laser output and the signal receiving device (6a) are respectively provided. There is a diode laser (61a), a first beam splitter (62a), a collimating lens (63a), and a four-quadrant photo detector (64a), as shown in the sixth figure. The internal outputs of the laser output and signal receiving device (61> are respectively equipped with a diode laser (61b), a first beam splitter (62b), a collimating lens (63b) and a four-quadrant light sensor ( 64b) [four-quadrant photo detector]. The first laser focus read head includes a laser output and signal receiving device (6a), a second beam splitter (7), an objective lens (8) (as shown in the fifth figure), and the projected beam is diode-shaped. The body laser (61 a) is directed to the first beam splitter (62a), and after passing through the first beam splitter (62a), the laser beam passes through a collimating lens (63a) to form a flat φ line beam, and then passes through a second beam splitting beam. The mirror (7) is then focused on the scale (10) via the objective lens (8), and the reflected beam follows the original path through the objective lens (8) and then through the second beam splitter (7), and then through the collimating lens (63a) The first beam splitter (62a) is then projected onto the four-quadrant light sensor (64a). The second laser focusing read head comprises a laser output and signal receiving device (6b), a mirror (9), a second beam splitter (7), and an objective lens (8) (as shown in the sixth figure). The projected beam is directed by a diode laser (6 lb) toward the first beam splitter (62b). After passing through the first beam splitter (62b), the laser beam passes through a collimating lens (63b) into a parallel beam, which is reflected. The mirror (9) rotates the parallel beam to 90 9 200842312 degrees, passes through the second beam splitter (7)' and then focuses on the scale (10) via the objective lens (8), while the reflected beam follows the original path through the objective lens (8). After that, it is projected onto the four-quadrant light sensor (64b) via the second beam splitter (7) 'via the mirror (9)' and then through the collimating lens (63b) and the first beam splitter (62b). The optical focusing principle of the laser focused read head of the present invention utilizes the astigmatism method in the focused Dong measurement method. The so-called astigmatism method refers to the difference in the imaging position between the horizontal and vertical directions during imaging, thus causing distortion of the image points, and utilizing this An astigmatism characteristic is used as the basis for measurement, so when the position of the surface of the grating ruler (10) is on the focal plane of the objective lens (8), the reflected light of the first-focus focusing read head passes through the second beam splitter (7)' and then passes through the collimating lens ( 63a) and the first-beam splitter ((4) will form a circular area on the four-quadrant light sensor (64a), while the second laser is focused. The reflected light of the head passes through the second beam splitter (7) and the mirror (9) Then, through the collimating lens-splitting sample, a circular area is formed on the four-quadrant light sensor (64b); if the surface of the grating ruler (10) is located in the non-focusing area of the objective lens (8), the -f(four)-focus reading The dichotomous surface (7), which is collimated through the # mirror_) and the dichroic mirror (62a), is formed on the four-quadrant photosensor (64a) in the shape of an elliptical shape and the second laser is focused. The read head passes through the second beam splitter (7) and the mirror (9), and then passes through the collimating lens ((4) sound first minute t (four) Μ # t The shape formed on the Μ Μ sensor is elliptical. When the scale (10) is in the unfocused position as shown in Fig. 5-A, then the first laser, the read head through the second beam splitter (7), the reflected light after the collimating lens and the first-splitting mirror (62a) will form a staggered elliptical spot in the four-quadrant light sensor (64a), and the second laser focused read head will pass through The second splitting light 200842312 mirror (7) and inverse (four) (9) 're-collimation lens ((4)) and the first-beam splitter (6 after the reflected light will be in the four-quadrant light sensor (64b) will form a wrong straight expansion Round spot; four-quadrant light sensor (64a~64b) signal is processed by self-made focus error processing circuit and is positive voltage output (ie, four-quadrant light sensor (64a~64b) (I +ΙΠ)· 〇ΐ+Ιν) is positive illusion; when the grating ruler (10) is located
第五圖·Β所示的聚焦位置時，反射光在四象限光感測器 (64a 64b)_L|成正®形光點，四象限光感㈣㈣〜64b) 訊號經聚焦誤差處理電路後為零電壓輸出〔即四象限光感 測器州〜⑽)之（Ι+ΙΠ⑽谓)為零電壓〕；當光栅尺⑽ 1 於It圖·⑶非聚焦位置時，反射光在四象限光感測器 ，〜）上形成水平橢圓光點，四象限光感測器d卿 訊=經聚：!、誤差訊贼理電路的處理後為負電壓輸 = =，64b)之(1，，為負電壓〕;In the focus position shown in the fifth figure Β, the reflected light is in the four-quadrant light sensor (64a 64b)_L| into a positive-shaped spot, and the four-quadrant light-sensing (four) (four) to 64b) is zero after the focus error processing circuit The voltage output (ie, the four-quadrant photo sensor state ~ (10)) (Ι + ΙΠ (10) is said to be zero voltage]; when the grating ruler (10) 1 is in the It diagram (3) unfocused position, the reflected light is in the four-quadrant light sensor , ~) on the formation of a horizontal elliptical spot, four-quadrant light sensor d Qing News = Jing:!, error signal thief circuit after the treatment is negative voltage = =, 64b) (1, is a negative voltage 〕;
與c三個訊號處理圖形，此對應第七圖之A、BAnd c three signals processing graphics, this corresponds to the seventh figure A, B
—们讯旒處理圖形的電壓輸出 構成弟八圖之聚焦誤差轉〔料為W 焦誤差電壓訊號〕，此綮隹嗜兰& & 縱釉马承 重要的2 線即為光學量測法中最 ΪΓΓΓ:線中的線性區域可作為位移量測 之用’為一動、靜態特性均優良之量測工具， 乃利用此-特性，將其制於量測光柵尺⑽之位移量， 將雷射聚焦讀頭與光柵尺⑽表面的距•好切 出电£ ’便可传到光柵尺⑽間距與表面高度的變化。 本發明之實施使用時’如第四、九圖所示，該雷射輸 200842312 出與訊號接收装置（6a〜6b)固定在旋轉調整座（55a〜55b) 上’又該旋轉調整座（55a〜55b)置於基座（5)上，以圓柱 (56a〜56b)為旋轉中心轉動，由於第一雷射聚焦讀頭與第二 雷射聚焦讀頭共用一第二分光鏡(7)與一物鏡(8)，使雷射輸 出與sfl號接收裝置(6a〜6b)輸出之兩準直光束，可由不同方 向經第二分光鏡(7)入射至物鏡(8)後同時聚焦於光柵尺（1〇) 上’再者’採用此單一物鏡(8)的設計方法，可使兩聚焦光 _ 點的相對距離相當接近，減少因兩個雷射聚焦讀頭之聚焦 光點距離太遠所造成的量測誤差，因此藉由精密微調螺絲 (52a〜52b)推動旋轉調整座（55a〜55b)，將可使兩雷射聚焦 光點的相對距離相等於四分之一光柵尺間距〔如第九圖所 示〕’再藉由螺絲（58a〜58b)與螺孔(59a〜59b)將旋轉調整座 (55a〜55b)鎖固於基座（5)上。當光柵尺（1〇)隨著精密機台移 動時，其光柵尺（10)的刻度高低，經由雷射輸出與訊號接 收裝置（6a〜6b)之四象限光感測器（64a〜64b)可量測到一個 • 聚焦誤差訊號〔即四象限之（I +ΠΗΠ+ΐν)〕，經聚焦誤差 處理電路後求得一組正交的弦波訊號，繼而利用訊號四分 割與細分割處理，計算出精密機台之移動方向與移動量。 而弦波訊號的形成則與二極體雷射（6U〜61b)的光波 波長、物鏡⑻的數值孔徑大小及光柵尺（1〇)的間距大小息 息相關，當二極體雷射(61a〜61b)的光波波長與光栅尺〇〇) 的間距大小相近時，如第十圖所示，雷射光束經光栅尺（1〇) 後會產生第〇階、士1階…等的繞射光束，因此可選擇具正 弦表面形狀之光栅尺（10)，並搭配適當數值孔徑的物鏡 12 200842312 (8)，使聚焦光點直徑小於光柵尺（10)間距，而直接由第〇 階繞射光束量取光栅尺（10)表面的輪廓變化，以庐得弦波 訊號；當二極體雷射（61a〜61b)的光波波長遠小於光柵尺 (10)的間距大小時’如第十—圖所示’雷射光束經光柵尺 ⑽後不會產生繞射光束，因此可選擇適當數值孔徑的物 鏡(8)’使聚焦光點直徑與光栅尺（10)的間距相近，如此將 可藉由直接量取光柵尺（10)表面的輪廓變化，以獲得弦波 訊號。 、 於田射XK焦f買頭之S曲線的實際量測，係先將一光柵 尺（10)固定，再利用精密步進馬達當做驅動軸推動雷射聚 :項頭首先將精密步進馬達的平臺移至離光柵尺（1〇)適 田位置，而後每次移動1μιη，到達定位時，觸發資料 ^取^ ’抓取雷射聚焦讀頭的輸出訊號〔聚焦誤差訊號〕 ^平至位私值，如此，可以得到平臺位置與雷射聚焦讀頭 輸出^聚焦誤差電壓訊號的對應關係，此關係便是S曲線 〔士第十一圖所示，橫軸為位移，而縱軸為聚焦誤差電壓 Α號輪出〕’由圖中可以清楚地看出S曲線中間的線性區 域部分具極佳的直線特性。 ^ 對於本發明之雙雷射聚焦讀頭光學尺的實驗驗證，係 採用市售間距為q·幻外m (1200 iine/mjn)、深度約〇·8μηι的線 ^生光拇尺’並選擇適當的雷射光波長與物鏡的數值孔徑， 使聚焦光點大小約為0·6μπι來進行實驗，整體實驗架設如第 十—圖所示’實驗中以精密步進馬達(a)帶動光柵尺（10)移 動’且定位過程中藉由SIOS公司所生產之雷射干涉儀(b)[型 13 200842312 號: SP-2000 TR]量測精密步進馬達⑷的位移值[亦即相等於 光栅尺（10)的位移值]，實驗中，整體量測以個人電腦（幻為 中心，先將雙雷射聚焦讀頭裝置(e)與光柵尺（1〇)表面的距 離恰好切入S曲線的線性區域内’且調整兩聚焦光點位置， 使兩聚焦光點的相對距離為四分之一光柵尺（10)間距大 小，而後驅動精密步進馬達⑷帶動光柵尺（10)移動，由個 人電腦（d)同步擷取雷射干涉儀(b)所量測到的精密步進馬 達(a)位移值與雙雷射聚焦讀頭裝置（c)所量測之光栅尺〇〇) ® 表面高度變化值，量測的輸出訊號如第十四圖所示，為— 組正交的弦波訊號圖，將這一組正交的弦波訊號繪製於呂 薩加空間（Lissajousspace)上，如第十五圖所示，得到一 正圓形圖形。 雙雷射聚焦讀頭光學尺的雜訊來源除了與電路設計中 所採用的電子元件與0P放大器（OP amplifiers)有密切關係 外，二極體雷射受環境溫度變化而造成光電流訊號的變動 φ 為一主要的訊號雜訊來源，本發明除選擇超低雜訊電子元 件與0P放大器作為系統的電路設計外，更設計一自動光功 率控制（Automatic Power Control)電路控制雷射輸出的穩 定性。 綜合以上所述，本發明採用光學聚焦量測具有極高位 移解析度與不易受到環境因素影響的光學量測特性，提高 雙雷射聚焦讀頭光學尺整體的量測精度。所完成的雙雷射 ♦焦頃頭光學尺，其正父訊號沒有存在著訊號直流準位偏 移、振幅不同及相對相位偏移等訊號不完美問題，且可經 200842312 由選擇不同物鏡的數值孔徑大小，來改變兩雷射聚焦光點 直徑的大小，使雙雷射聚焦讀頭可應用於各種不同間距大 小的光柵尺。因此本發明確具有新穎性與實用性，量測方 法具獨特性，應符專利申請要件，爰於法提出申請。 惟上述實施例僅為說明本發明之原理及其功效，而非 用以限制本發明，本發明所主張之權利範圍自應以申請專 利範圍所述為準。 【圖式簡單說明】 * 第一圖：係為習用光學尺製作方法之示意圖。 第二圖：係為本發明之立體分解圖。 第三圖：係為本發明之立體組合圖。 ' 第四圖：係為本發明之上視圖。 第五圖：係為本發明雷射聚焦讀頭之構造示意圖。 第六圖：係為本發明雷射聚焦讀頭之構造示意圖。 弟七圖·係為本發明四象限光感測器之訊號處理不意圖。 Φ 第八圖：係為本發明s曲線之示意圖。 第九圖：係為本發明兩聚焦光點距離相等於四分之一光柵 尺間距之調整示意圖。 第十圖：係為本發明光波波長與光柵尺間距相近之光柵尺 表面量測原理示意圖。 第十一圖：係為本發明光柵尺間距遠大於光波波長之光柵 尺表面量測原理示意圖。 第十二圖：係為本發明S曲線實驗數據示意圖。 第十三圖：係為本發明雙雷射聚焦讀頭光學尺整體實驗示 15 200842312 意圖。 第十四圖：係為本發明正交弦波訊號實驗數據圖 弟十五圖·係為本發明正交弦波訊號緣製於呂缝 (Lissajous space )的數據圖。 < 間 【主要元件符號說明】 (5) 基座 （51)鏡組固定$ (52a〜52b) 精密微調螺絲（53a〜53b) 項斜- The voltage output of the processing signal forms the focus error of the figure 8 (the material is the W-focus error voltage signal), and the important 2 lines of the vertical glaze horse is the optical measurement method. The most ambiguous: the linear region in the line can be used as a measurement tool for displacement measurement. It is a measurement tool with excellent dynamic characteristics and static characteristics. It is used to measure the displacement of the grating scale (10). The distance between the focus reading head and the surface of the grating ruler (10) can be transmitted to the grating (10) and the height of the surface. When the implementation of the present invention is used, as shown in the fourth and ninth diagrams, the laser transmission 200842312 and the signal receiving device (6a to 6b) are fixed to the rotation adjusting seats (55a to 55b), and the rotating adjustment seat (55a) ~55b) is placed on the base (5), and rotates with the cylinder (56a~56b) as a center of rotation, since the first laser focus read head shares a second beam splitter (7) with the second laser focus read head. An objective lens (8), the two collimated beams outputted by the laser output and the sfl receiving device (6a~6b) can be incident on the objective lens (8) through the second beam splitter (7) in different directions and then focused on the grating (1〇) On the 'further', the design method of this single objective lens (8) can make the relative distances of the two focused lights _ points quite close, reducing the distance from the focused spot of the two laser focusing read heads. The resulting measurement error, so by rotating the fine adjustment screws (52a~52b) to rotate the adjustment seats (55a~55b), the relative distance between the two laser focused spots will be equal to the quarter-grating distance [eg The ninth figure] 'The locks (55a~55b) are locked by the screws (58a~58b) and the screw holes (59a~59b). Fastened to the base (5). When the scale (1〇) moves with the precision machine, the scale of the scale (10) is high and low, and the four-quadrant light sensor (64a~64b) via the laser output and signal receiving device (6a~6b) A • focus error signal (ie, four quadrants (I + ΠΗΠ + ΐν)) can be measured, and a set of orthogonal sine wave signals is obtained after the focus error processing circuit, and then the signal is divided and finely divided, Calculate the moving direction and movement amount of the precision machine. The formation of the sine wave signal is closely related to the wavelength of the light of the diode laser (6U~61b), the numerical aperture of the objective lens (8) and the spacing of the grating scale (1〇), when the diode laser (61a~61b) When the wavelength of the light wave is close to the pitch of the grating, as shown in the tenth figure, the laser beam will generate a diffracted beam of the second order, the first order, etc. after passing through the grating (1〇). Therefore, the grating scale (10) having a sinusoidal surface shape can be selected, and the objective lens 12 200842312 (8) with a suitable numerical aperture is used to make the focal spot diameter smaller than the grating ruler (10) pitch, and the amount of the diffracted beam directly from the second order. Take the contour change of the surface of the grating ruler (10) to obtain the sine wave signal; when the wavelength of the light wave of the diode laser (61a~61b) is much smaller than the pitch of the grating ruler (10), as in the tenth-picture It is shown that the laser beam does not generate a diffracted beam after passing through the grating (10), so the objective lens (8) of the appropriate numerical aperture can be selected to make the diameter of the focused spot close to the distance of the grating (10), so that it can be directly The contour of the surface of the scale (10) is measured to obtain a sine wave signal. The actual measurement of the S-curve of the X-ray shooting head of Yutian is fixed by first fixing a grating ruler (10), and then using a precision stepping motor as a driving shaft to push the laser beam: the head first will be a precision stepping motor. The platform is moved to the position of the grating scale (1〇), and then moved 1μιη each time. When the positioning is reached, the trigger data is taken. ^ 'Grab the output signal of the laser focus read head [focus error signal] ^ Ping in place The private value, in this way, can obtain the correspondence between the position of the platform and the laser focus read head output ^ focus error voltage signal, the relationship is the S curve [the eleventh figure, the horizontal axis is the displacement, and the vertical axis is the focus The error voltage Α is rotated out] ' It can be clearly seen from the figure that the linear region in the middle of the S curve has excellent linear characteristics. ^ For the experimental verification of the double-laser focusing read head optical scale of the present invention, a line of commercially available pitches of q·magic outer m (1200 iine/mjn) and a depth of about 〇·8μηι is selected and selected. The appropriate laser light wavelength and the numerical aperture of the objective lens are used to make the focused spot size about 0·6μπι to carry out the experiment. The overall experiment is set up as shown in the tenth figure. The experiment uses a precision stepping motor (a) to drive the grating scale ( 10) Mobile' and the displacement of the precision stepper motor (4) is measured by the laser interferometer (b) [Model 13 200842312: SP-2000 TR] produced by SIOS [in the positioning process] (10) Displacement value], in the experiment, the overall measurement is based on the personal computer (the magic center, the distance between the double laser focusing read head device (e) and the grating scale (1〇) surface is cut into the linearity of the S curve. In the area, and adjust the position of the two focused spots, the relative distance between the two focused spots is a quarter of a grating (10) spacing, and then the precision stepping motor (4) drives the grating (10) to move, by the personal computer. (d) Synchronous sampling of the precision stepper measured by the laser interferometer (b) (a) displacement value and the grating scale measured by the dual laser focusing read head device (c) 表面) surface height variation value, the measured output signal is as shown in Figure 14 The sinusoidal signal map plots the orthogonal sinusoidal signals on the Lissajous space, as shown in the fifteenth figure, to obtain a perfect circular pattern. In addition to the close relationship between the electronic components and the OP amplifiers used in the circuit design, the diode laser is subject to changes in ambient temperature due to changes in ambient current temperature. φ is a main source of signal noise. In addition to selecting ultra-low noise electronic components and 0P amplifiers as the circuit design of the system, the invention also designs an automatic power control circuit to control the stability of the laser output. . In summary, the present invention uses optical focusing measurement to have an extremely high displacement resolution and an optical measurement characteristic that is not susceptible to environmental factors, and improves the overall measurement accuracy of the dual laser focusing read head optical scale. The completed double-laser ♦ focal length optical scale has no signal imperfection problem such as signal DC offset, amplitude difference and relative phase offset, and the value of different objective lens can be selected by 200842312. The aperture size is used to change the diameter of the two laser focused spot points, so that the dual laser focusing read head can be applied to grating scales of various pitch sizes. Therefore, the present invention has novelty and practicability, and the measurement method is unique, and should meet the requirements of the patent application, and apply in the law. The above-mentioned embodiments are merely illustrative of the principles of the invention and the advantages thereof, and are not intended to limit the scope of the invention. [Simple description of the diagram] * First diagram: It is a schematic diagram of the method of making a conventional optical ruler. Second figure: is a perspective exploded view of the present invention. The third figure is a three-dimensional combination diagram of the present invention. 'Fourth figure: is a top view of the invention. Fig. 5 is a schematic view showing the structure of the laser focusing read head of the present invention. Fig. 6 is a schematic view showing the structure of a laser focusing read head of the present invention. The seventh figure is not intended for the signal processing of the four-quadrant light sensor of the present invention. Φ Figure 8 is a schematic diagram of the s curve of the present invention. Fig. 9 is a schematic diagram showing the adjustment of the distance between two focused spots of the invention equal to the pitch of the quarter grating. The tenth figure is a schematic diagram of the principle of measuring the surface of the grating with the wavelength of the light wave and the distance between the gratings. Figure 11 is a schematic diagram showing the principle of measuring the surface of a grating scale with a grating pitch far greater than the wavelength of the light wave. Twelfth figure: is a schematic diagram of the experimental data of the S curve of the present invention. Thirteenth Picture: The overall experimental demonstration of the double laser focusing read head optical scale of the present invention 15 200842312 Intent. Figure 14: This is the experimental data of the orthogonal sine wave signal of the present invention. The fifteenth figure is the data diagram of the sinusoidal sine wave signal of the invention in Lissajous space. < Between [Main component symbol description] (5) Base (51) Mirror group fixed $ (52a~52b) Precision fine adjustment screw (53a~53b)
(54a〜54b) 彈簧 （55a〜55b)旋轉調整座 (551a〜5$lb)貫穿孔 （552a〜552b)弧形槽 (56a〜56b)圓柱 （57a〜57b)頂針座 (58a〜58b)螺絲 （59a〜59b)螺孔 (6a〜6b)雷射訊號發射與接收裝置 (61a〜61b) 二極體雷射 （62a〜62b) 第一分光鏡 (63a〜63b) 準直透鏡 (64a〜64b) 四象限光感測器 ⑺ 第二分光鏡 ⑻ 物鏡 (9) 反射鏡 (10) 光栅尺 ⑻ 精密步進馬達 (b) 雷射干涉儀 ⑷ 雙雷射聚焦讀頭裝置 (d) 個人電腦 16(54a to 54b) Springs (55a to 55b) Rotating adjustment seats (551a to 5$lb) through holes (552a to 552b) arcuate grooves (56a to 56b) cylindrical (57a to 57b) thimble seats (58a to 58b) (59a~59b) Screw hole (6a~6b) Laser signal transmitting and receiving device (61a~61b) Diode laser (62a~62b) First beam splitter (63a~63b) Collimating lens (64a~64b) Four-quadrant light sensor (7) Second beam splitter (8) Objective lens (9) Mirror (10) Scale (8) Precision stepper motor (b) Laser interferometer (4) Double laser focus read head device (d) Personal computer 16