1250781 八本有，時，請揭示最能顯示發明特徵的化 學式·（略） 九、發明說明： 【發明所屬之技術領域】 本發明係有關一種雷射掃晦裝置（LSU )的f㊀鏡片 及其製法，尤指一種具有多區域光學面（multi—secti〇ns optical surfac^)鏡片，藉以取代習知【0鏡片每 一光學面只具單一參數組之結構設計，而可達到高公差 (high tolerance )之組裝品質及高效率（high per f ormance )之掃瞄效果者。 【先前技術】 按’目别雷射光束印表機LBP (Laser Beam Printer ) 之應用技術中，已包括有：美國US 5,128, 795、 US5,162, 938、US 5, 329, 399、US 5, 710, 654、US 5,757,533、US 5,619,362、US5,721，631、US 5,553, 729、US 5,111,219、US 5,995,131，及日本 4-50908、日本5-45580等多件專利，其中，所使用之雷 射掃瞒裝置LSU ( Laser Scanning Unit )模組大都是利用 一高速旋轉（如40000/min)之多面鏡（polygon mirror ) (如四或六面）以操控雷射光束之掃猫動作（laser beam scanning )，茲以一習知雷射掃猫裝置（LSU ) 1說明一 般LSU之結構型態及光學路徑如下：如第1、1A、1B圖所 示，以一半導體雷射10作光源而發出雷射光束（laser 1250781 beam ) ’該雷射光束可先經一細孔（aperture ) 11再經過 一準直鏡（collimator ) 12，而準直鏡12可使雷射光束形 成平行光束，平行光束再經過一柱面鏡（cylindrical lens) 13，而該柱面鏡13主要作用係使前述平行光束在副 掃瞄方向（sub-major scanning direction ) Y 轴上之寬度 能沿著主掃瞒方向（major scanning direction ) X轴（如 箭頭所示）之平行方向聚焦而形成一線狀成像（line image )(在第1B圖中聚焦成一點）；又利用一可高速旋 轉之多面鏡（polygon mirror ) 14，使其上均勻連續佈設 之多面反射面（鏡面）15恰位於或接近於上述線狀成像 (line image )之焦點位置；而多面鏡14係用以控制雷射 光束之投射方向，其上連續之複數反射面15在高速旋轉時 可將入射至反射面15上之雷射光束沿著主掃瞄方向（X 轴）之平行方向以同一轉角速度（angular velocity )偏 斜反射至一 f 0鏡片16上；而該f 0鏡片16係設置於多面 鏡14旁侧’可爲單件式鏡片結構（single-element scanning lens )如第1圖所示，或爲兩件式鏡片結構（如 US 5, 995,131專利圖所示），而藉f 0鏡片π通常是使經 由多面鏡14上反射面15而射入之雷射光束能聚焦成一圓形 光點（circular light spot )並投射在一光接收面 (photoreceptor drum) 17上，以達成線性掃瞄（scanning linearity )的要求。 而上述習知LSU 1中之f Θ鏡片16，其實體構造係如 第2圖所示之ίθ鏡片2，而其光學面之設計係引用下列 1250781 幾種方程式及參數的組成： 1. Anamorphic surface: z. 你># +獅 a?2 • i7 (i (i ^ Rx) ccx)2 ccy)2 ♦職((：!-»，）#♦ α + Β，>ϊ^ ♦ CR ¢(1 替 CF> ♦ (1 + C»> ♦職(（1 · ®f》# + a + 膽> 其中， Z :就是sag，就一曲面鏡片而言，Z軸為此鏡片的光軸 在鏡片曲面上 (Optical Axis)，以曲面中心為零點 的不同位置，平行Z軸方向與χγ平面的高度差 而各麥數界定如下：1250781 When there are eight, please disclose the chemical formula that best shows the characteristics of the invention. (Omitted) 9. Description of the invention: [Technical field of the invention] The present invention relates to a lens of a laser broom device (LSU) and The method of manufacturing, in particular, a multi-secti-optic optical surfac^ lens, in place of the conventional [0 lens, each optical surface has a single parameter group structure design, and can achieve high tolerance (high tolerance ) The assembly quality and high efficiency (high per f ormance) scan effect. [Prior Art] In the application technology of the 'Laser Beam Printer', the following technologies have been included: US 5,128,795, US 5,162,938, US 5,329,399, US 5 , 710, 654, US 5, 757, 533, US 5, 619, 362, US 5, 721, 631, US 5, 553, 729, US 5, 111, 219, US 5, 995, 131, and Japanese 4-50908, Japanese 5-45580, etc., wherein the laser used Most of the LSU (Laser Scanning Unit) modules use a high-speed rotating (such as 40,000/min) polygon mirror (such as four or six sides) to control the laser beam scanning of laser beams. The structure and optical path of a general LSU are as follows: as shown in Figures 1, 1A and 1B, a semiconductor laser 10 is used as a light source to emit a thunder. Beam (laser 1250781 beam) 'The laser beam can pass through an aperture 11 and then through a collimator 12, and the collimating mirror 12 can form a parallel beam of laser beams, parallel beams Passing through a cylindrical lens 13, and the cylindrical mirror 13 is mainly The line is formed such that the width of the parallel beam in the sub-major scanning direction on the Y-axis can be focused in a parallel direction of the main scanning direction X-axis (as indicated by the arrow) to form a line. Line image (focusing on a point in Fig. 1B); using a polygon mirror 14 that can be rotated at a high speed to make the multi-faceted reflecting surface (mirror) 15 uniformly spaced continuously on or near In the above-mentioned focus position of the line image; the polygon mirror 14 is used to control the projection direction of the laser beam, and the continuous multi-reflection surface 15 can be incident on the reflection surface 15 at a high speed rotation. The beam is deflected at a same angular velocity in the parallel direction of the main scanning direction (X-axis) onto a f 0 lens 16; and the f 0 lens 16 is disposed beside the polygon mirror 14 For a single-element scanning lens, as shown in Figure 1, or a two-piece lens structure (as shown in the US Pat. No. 5,995,131), the f 0 lens π is usually made through multiple faces. Mirror 14 The laser beam incident on the reflecting surface 15 can be focused into a circular light spot and projected onto a photoreceptor drum 17 to achieve a linear linearity requirement. The f Θ lens 16 of the above-mentioned conventional LSU 1 has a physical structure such as the ίθ lens 2 shown in FIG. 2, and the design of the optical surface thereof is composed of the following 1250781 several equations and parameters: 1. Anamorphic surface : z. You># + lion a?2 • i7 (i (i ^ Rx) ccx)2 ccy)2 ♦ job ((:!-»,)#♦ α + Β,>ϊ^ ♦ CR ¢ (1 for CF> ♦ (1 + C»> ♦ job ((1 · ®f)# + a + 胆> where Z: is sag, for a curved lens, the Z axis is the light for this lens The axis is on the surface of the lens (Optical Axis), with different positions at the center of the surface at zero, and the height difference between the parallel Z-axis direction and the χγ plane is defined as follows:
Cx : X方向的曲率，即為曲率半徑1^的倒數 Cy : Y方向的曲率，即為曲率半徑Ry的倒數 Kx : X 方向的 Conic ConstantCx : the curvature in the X direction, which is the reciprocal of the radius of curvature 1 ^ Cy : the curvature in the Y direction, which is the reciprocal of the radius of curvature Ry Kx : Conic Constant in the X direction
Ky : Y 方向的 Conic Constant AR : X與Y四次冪的對稱型非球面係數 BR : X與Υ六次冪的對稱型非球面係數 CR : X與Υ八次冪的對稱型非球面係數 DR : X與Υ十次冪的對稱型非球面係數 AP : X與Υ四次冪的非對稱型非球面係數 BP : X與Υ六次冪的非對稱型非球面係數 CP : X與Υ八次冪的非對稱型非球面係數 DP : X與Υ十次冪的非對稱型非球面係數 1250781 2. First Type Toric surface:Ky : Conic Constant AR in the Y direction: Symmetrical aspheric coefficient of the fourth power of X and Y BR : Symmetric aspheric coefficient CR of X and Υ power of six: Symmetrical aspheric coefficient DR of X and Υ8 power : Symmetrical aspherical coefficients of X and Υ10 powers AP: Asymmetric aspheric coefficients BP of X and Υ4 powers: Asymmetric aspheric coefficients of X and Υ6 powers CP: X and Υ8 times The asymmetry-type aspheric coefficient of power DP: X and the asymmetry-type aspherical coefficient of Υ10 powers of 1250781 2. First Type Toric surface:
Gwy2 Z = F+ - 1 + 々 1 - G2 貪 y2 F = --—...— + M + M *x6 + M #x8 + 3110 ^ac10 ; 1+ V 1- (1 + Kx) itCx2 ^χ2 π Cx G=-;Gwy2 Z = F+ - 1 + 々1 - G2 greedy y2 F = ---...- + M + M *x6 + M #x8 + 3110 ^ac10 ; 1+ V 1- (1 + Kx) itCx2 ^χ2 π Cx G=-;
1-Cx*F 其中，各參數界定如下：1-Cx*F where each parameter is defined as follows:
Cx : X方向的曲率Cx : curvature in the X direction
Kx : X 方向的 Conic Constant F : X 方向的Sag value G : Y方向的曲率，會隨不同X位置有所改變 Α4〜Α10 :分別為X的四、六、八、十次冪的非球面係數 3. Second Type Toric surface: Z= - + B2 » x2 + B4 Itx4 + B6 w x6 +B8 irX8 + BIO *3^ 1 + + K>* (x/R)2 r 1 = r (1 + 02*3^ +D4*x4 +D6*x6 +D8 wx8 +010*3^} 其中，各參數界定如下： R : X方向的曲率半徑（此處之R即為Rx ) K : X方向的Conic Constant (此處之K即為Kx ) B2〜B10:分別為X的二、四、六、八、十次冪的非球面係數 r’ ：非球面上法線方向的曲率半徑值 D2〜D10 :多項式係數 1250781 而由上述設計方程式及參數，可知習知單件式f㊀鏡 片2之光學面21、22皆係由單一光學參數組 (coefficient set )構成，亦即f㊀鏡片之第一光學面21 及第二光學面22分別由單一參數組構成，如此設計雖可使 第一、二光學面21、22皆呈連續式光學面型（continuing surf ace prof i le )，但在使用上會有下列問題： (1 )、f <9鏡片之主要功能係將射入之雷射光束 聚焦成一圓形光點（circular light spot )並以線性掃瞄 (scanning linearity)方式投射在一光接收面 (photoreceptor drum)上，而該圓形光點（circular light spot )之成像要求最好是在線性掃瞄上成像直徑爲 30μπι之圓形光點，或至少是在ΙΟΟμπι直徑之圓範圍内；然 以習知LSU之組裝型態（參照第1圖）而言，投射至多面 鏡14反射面15而再反射入f Θ鏡片的雷射光束中心轴，顯 然並非正對多面鏡14之中心轉軸，因此在設計相配合之f Θ鏡片時，須同時考慮多面鏡14之離軸偏差（deviation ) 問題，致最佳化的f Θ鏡片之光學面存在有非對稱性的本 質(unsymmetrical characteristics ) 〇 (2 )、而因f Θ鏡片之光學面既具有光學非對稱 性區域（unsymmetrical optical field)，而又須達成線性 掃瞄（scanning linearity)要求，已使f Θ鏡片之設計困 難度提高，因此當習知f Θ鏡片之光學面只以單一參數組 設計時，則須在單一參數組上作出各種妥協性或平衡性修 改，藉以兼顧左、右非對稱性區域的光學面條件，然此不 1250781 但增加f㊀鏡片之設計麻煩，也使妥協設計（Trade-off) 後之單一參數組無法同時以高程度來滿足左、右非對稱性 區域之光學面要求，致使左、右非對稱性區域之光學效率 相對降低，如第3圖所示，其係以一利用單一參數組設計 之f Θ鏡片2 (如第2圖所示）做光學模擬實驗，其中所 示包括多面鏡23、多面反射面（鏡面）24、雷射光束25及 光接收面（photoreceptor drum) 26，可知其在單位距離呈 現之光點（light spot ) 27，不但形成多種形狀而非圓形 光點（circular light spot )，且其光點也有偏離1〇〇_ 直控圓之中心者，甚至有超出直徑圓之範圍外，倶 表示妥協後單一參數組之設計已使左、右光學非對稱性區 域之光學效率相對降低，也相對形成低公差（tolerance) 而增加組裝之困難度；此乃習知f θ鏡片結構設計上最大 遺憾。 【發明内容】 本發明主要目的乃在於提供一種雷射掃瞄裝置的f㊀ 鏡片’其係使ί Θ鏡片之光學面（optical surface )分由 多區域（multi-sections )構成，且各區域之光學面係依 各區域相對於雷射光束之不同位置或角度而設具不同光學 參數組（coefficient set )，藉以避免習知f㊀鏡片每一 光學面只具單一參數組的缺點，而可減少f㊀鏡片設計之 困難度，並能達成高效率（high performance )及高公差 (high tolerance )之掃瞄效果。 本發明再一目的乃在於提供一種雷射掃瞄裝置的f θ 1250781 鏡片的製法，其製法包括下列步驟：先設定一f θ鏡片之 區域數，如2_sections〜n-sections，並針對各區域而模 擬實驗出一最佳參數組，藉以構成該區域之光學面；再針 對二不同區域的光學面交界處可能産生的曲面斷差，利用 模擬式曲面修正（curve fitting)及光學模擬實驗 (optical simulation)，藉以在二不同區域之光學面交界 處確定一最佳的平滑連續面型（continuing surf ace profile );再利用超精密機械加工方式，如利用數位控 制（NC)程式來設定刀具路徑（SAG值）而進行機械加 工’猎以完成一具多區域光學面（multi-sections optical surface )之f Θ鏡片的成型模具；再利用該f θ鏡片成 型模具進行模具射出成型（injection molding )製程，而 里産化製成上述具多區域光學面（multi - sections optical surface )結構之f㊀鏡。 爲使本發明更加明確詳實，茲配合下列圖示將本發明 之結構及其技術特徵詳述如後： 【實施方式】 本發明雷射掃瞄裝置的f Θ鏡片，其結構特徵在於： 该f Θ鏡片係分由多區域（一)構成，且各 區域之光學面（optical surface)係依各區域相對於入射 雷射光束的不同位置或角度而設具不同光學參數組 (coefficient set )。參考第4圖所示，該f Θ鏡片3係 以一分界線3a分成二等區域（2-sections )，包括第一區 1250781 域31及第二區域32 ;再參考第4A圖，該f Θ鏡片4係以二 分界線4a分成三等區域（3_sections )，包括第一區域 41、 第二區域42及第三區域43 ;而依此類推，可依需要而 將一 f Θ鏡分成多區域（multi-sections );又本發明f Θ鏡片上各區域之主要光學面（〇pt ical surf ace )，如f Θ鏡片3上之光學面311、312、321、322共四面光學 面，或f Θ鏡片4上之光學面411、412、421、422、 431、432共六面光學面，係依各區域31、32 (或41、 42、 43)在ίθ鏡片3 (或4)上之不同位置，亦即各區 域31、32 (或41、42、43)相對於入射雷射光束的不同位 置或角度，而設具不同之光學參數組（coefficient set )，使f Θ鏡片3或4上不同區域之數個光學面分別 由一最佳光學參數組構成，進而使形成之具多區域光學面 (multi-sections optical surface ) ίθ 鏡片 3 或4 可達 成高公差（high tolerance )之組裝品質及高效率（high performance )之掃瞎效果。 再參考第5、5A、6、6A圖，其係以一具二區域光學 面（2-sections optical surface )之 f Θ鏡片 3 爲例，由 於第一區域31及第二區域32之光學面係由不同之光學參數 組（coefficient set )構成，致第一區域31及第二區域32 二不同區域之光學面交界處可能會産生不同程度之曲面斷 差，其中以f Θ鏡片之邊緣端處産生之斷差最大，如第5A 或6A圖所示之斷差5 ;而針對該可能産生之斷差5，可先 進行模擬的曲面修正（curve fitting)，並將模擬修正後 1250781 之曲面再經光學模擬實驗（optical simulation)，藉以確 定一最佳之平滑連續面型（continuing surface profile ) 51，再利用超精密機械加工方式，如利用數位控制（NC) 程式來設定刀具路徑（SAG值），藉以完成一具多區域光 學面（multi-sections optical surface )之 f Θ鏡片成型 模具，使成型模具中二不同區域之光學面交界處具有最佳 之平滑連續面型（continuing surface profile )，而成爲 ί Θ鏡片之模具射出成型（injection molding )之模具。 又本發明f Θ鏡片設計成具多區域光學面 (multi-sections optical surface )結構，確實可克服習 知f Θ鏡片每一光學面只具單一參數組之結構設計問題， 茲舉一較佳實施例做進一步說明，請參考第7、8圖，其 係一具一區域光學面（2-sections optical surface )之 f Θ鏡片3，而各區域光學面，包括第一區域之光學面 311、312及第二區域之光學面321、322分別由一組參 數組構成如第7圖所示之四組參數組；而其成像光點之品 質如第8圖所示，在左上方及右下方所示各五個1〇〇咖直 徑圓所示之光點81係本發明f㊀鏡片之成像品質，而在左 下方及右上方所示各四個1〇〇μιη直徑圓所示之光點犯係習 知f Θ鏡片之成像品質，二者間加以比較，可知本發明f Θ鏡片之成像光點品質顯然優於習知ίθ鏡片。 再參考第9圖，本發明具多區域光學面 (multi-sections optical surface )結構之 f ㊀鏡片，其 製法包括下列步驟： 〃 1250781 先设疋一 f㊀鏡片的區域數，如2-sections〜 n-sections，並針對各區域，如第一區域（secti〇n 1)、 第一區域（section 2 )· ·第 η 區域（section η)，而模 擬實驗出一最佳參數組，藉以構成該區域之光學面； 再針對一不同區域的光學面交界處可能産生的曲面斷 差’利用擬實式曲面修正（curve fitting )及光學模擬實 驗（optical simulation)，藉以在二不同區域之光學面交 界處確定一最佳之平滑連續面型（continuing surf ace profile ) ; ® 再利用超精密機械加工方式，如利用數位控制（NC ) 程式來設定刀具路徑（SAG值），來進行模具的機械加 工’藉以完成一具多區域光學面（multi-sections optical surf ace )之ίθ鏡片的成型模具； 再利用該f Θ鏡片成型模具進行模具射出成型 (injection molding )製程，藉以量産化製成具多區域光 學面（multi-sections optical surface )結構之 f Θ鏡 片。 · 综上所述，本發明的確能藉由上述所揭露之結構達到 所預期之功效，且本發明申請前未見於刊物亦未公開使 用’誠已符合專利之新颖、進步等要件。 惟，上述所揭之圖式及說明，僅爲本發明之實施例而 已’非爲限定本發明之實施例；大凡熟悉該項技藝之人 士，其所依本發明之特徵範疇，所作之其他等效變化或修 飾，皆應涵蓋在以下本案之申請專利範圍内。 12 1250781 【圖式簡單說明】 第1圖：係習知一雷射掃瞄裝置模組之立體圖。 第1A圖：係第1圖光學路徑之上視圖。 第1B圖：係第1圖光學路徑之一側視圖。 第2圖：係習知一 f Θ鏡片其光學面只具單一參數組之結 構圖。 第3圖··係習知利用單一參數組設計之f Θ鏡片經模擬實 驗之光點（light spot )示意圖。 第4圖：係本發明一具二區域（2-sections )光學面實施 例之分區示意圖。 第4A圖：係本發明一具三區域（3-sections )光學面實施 例之分區示意圖。 第5圖··係本發明一具二區域（2-sections )光學面實施 例之結構上視圖。 第5A圖··係第5圖中5A-5A之剖視圖。 第6圖：係第5圖之結構侧視圖。 第6A圖：係第6圖中6A-6A之剖視圖。 第7圖：係本發明一具二區域（2-sections )光學面之f ㊀鏡片實施例之結構圖。 第8圖··係第7圖經模擬實驗之光點（light spot )示意 圖。（包括未分區域的光點比較） 第9圖··係本發明具多區域光學面（multi-sections optical surface )之f Θ鏡片的製法方塊圖。 13 1250781 【主要元件符號說明】 雷射掃瞄裝置1 半導體雷射 10 細孔 11 準直鏡 12 柱面鏡 13 多面鏡 14 反射面 15 f Θ鏡片 16 光接收面 17 f Θ鏡片 2 光學面 21 > 22 f㊀鏡片 3 分界線 3a、4a 區域 31 區域 41、42、43 光學面 311 、 312 、 321 、322 光學面 411 、 412 、 421 、422、431、 432 斷差 5 平滑連續面型！Kx : Coonic Constant F in X direction: Sag value in X direction G : Curvature in Y direction will change with different X positions Α4~Α10: Aspheric coefficients of X, 6, 8, and 10 powers, respectively 3. Second Type Toric surface: Z= - + B2 » x2 + B4 Itx4 + B6 w x6 +B8 irX8 + BIO *3^ 1 + + K>* (x/R)2 r 1 = r (1 + 02* 3^ +D4*x4 +D6*x6 +D8 wx8 +010*3^} where the parameters are defined as follows: R : radius of curvature in the X direction (where R is Rx) K : Conic Constant in the X direction Here K is Kx) B2~B10: aspherical coefficients r' of the second, fourth, sixth, eighth, and tenth powers of X: the radius of curvature of the normal direction of the aspherical surface D2~D10: polynomial coefficient 1250781 From the above design equations and parameters, it can be seen that the optical surfaces 21, 22 of the conventional one-piece f-lens 2 are composed of a single optical parameter set, that is, the first optical surface 21 and the second of the f-lens. The optical surfaces 22 are respectively composed of a single parameter group. The design allows the first and second optical surfaces 21 and 22 to have a continuous optical surface (continuation surf ace prof i le ), but in use. There are the following problems: (1), f < 9 The main function of the lens is to focus the incident laser beam into a circular light spot and project it in a linear scan (scanning linearity) On the receiving surface (photoreceptor drum), the imaging requirement of the circular light spot is preferably to image a circular spot having a diameter of 30 μm on a linear scan, or at least within a circle of a diameter of ΙΟΟμπι However, in the assembled form of the conventional LSU (refer to FIG. 1), the center axis of the laser beam projected onto the reflecting surface 15 of the polygon mirror 14 and reflected into the f Θ lens is obviously not the center of the polygon mirror 14 The rotating shaft, therefore, in designing the matching f Θ lens, the off-axis deviation of the polygon mirror 14 must be considered at the same time, so that the optical surface of the optimized f Θ lens has an asymmetric characteristic (unsymmetrical characteristics). 〇(2), because the optical surface of the f Θ lens has both an optically asymmetric field and a linear linearization requirement, which has made the design of the f Θ lens difficult. The difficulty is improved, so when the optical surface of the conventional lens is designed in a single parameter group, various compromises or balance modifications must be made on a single parameter group, thereby taking into account the optical surface conditions of the left and right asymmetrical regions. However, this is not 1250781. However, the design of the lens is more troublesome, and the single parameter group after the Trade-off design cannot meet the optical surface requirements of the left and right asymmetrical regions at the same time, resulting in left and right. The optical efficiency of the asymmetric region is relatively reduced. As shown in Fig. 3, it is an optical simulation experiment using a single parameter set of the Θ lens 2 (as shown in Fig. 2), which includes a polygon mirror. 23. A multi-faceted reflecting surface (mirror) 24, a laser beam 25, and a photoreceptor drum 26, which are known to present a light spot 27 at a unit distance, not only forming a plurality of shapes but not a circular spot ( Circular light spot ), and its light spot also deviates from the center of the 1控_ direct control circle, even beyond the diameter circle, 倶 indicates that the design of the single parameter group has made the left and right light The optical efficiency of the asymmetric region is relatively reduced, and the difficulty of assembly is increased relative to the formation of low tolerance; this is the most regrettable design of the conventional f θ lens structure. SUMMARY OF THE INVENTION The main object of the present invention is to provide a lens of a laser scanning device which is formed by multi-sections of optical surfaces of λ lenses and optical regions of the respective regions. The surface system is provided with different optical parameter sets according to different positions or angles of the laser beams, so as to avoid the disadvantage that the optical surface of each lens has only a single parameter group, and the lens can be reduced. The difficulty of design and the ability to achieve high performance and high tolerance scanning results. Another object of the present invention is to provide a method for manufacturing a f θ 1250781 lens of a laser scanning device, which comprises the steps of: first setting a number of regions of an f θ lens, such as 2_sections~n-sections, and for each region. The simulation experiment shows an optimal parameter set to form the optical surface of the region; then, for the surface faults that may occur at the intersection of the optical surfaces of the two different regions, the curved surface correction and optical simulation experiments are used. ), in order to determine an optimal continuation surf ace profile at the intersection of the optical surfaces of the two different regions; and then use ultra-precise machining methods, such as using the digital control (NC) program to set the tool path (SAG) And machining to complete a molding die of a multi-section optical surface; and then using the fθ lens molding die to perform an injection molding process; The above-described production is made into the above-mentioned multi-section optical surface structure. In order to make the present invention clearer and more detailed, the structure and technical features of the present invention will be described in detail below with reference to the following drawings: [Embodiment] The f Θ lens of the laser scanning device of the present invention is characterized in that: The Θ lens is composed of a plurality of regions (1), and the optical surfaces of the regions are provided with different optical parameter sets according to different positions or angles of the regions with respect to the incident laser beam. Referring to FIG. 4, the f-lens lens 3 is divided into second-section regions (2-sections) by a boundary line 3a, including a first region 1250781 domain 31 and a second region 32; and referring to FIG. 4A, the f Θ The lens 4 is divided into three equal sections (3_sections) by a boundary line 4a, including a first area 41, a second area 42, and a third area 43; and so on, a f-mirror can be divided into multiple areas as needed (multi -sections); the main optical surface of each region on the lens of the present invention, such as the optical surface 311, 312, 321, 322 on the f Θ lens 3, or the f Θ lens 4 optical surfaces 411, 412, 421, 422, 431, 432 have a total of six optical surfaces, depending on the respective regions 31, 32 (or 41, 42, 43) at different positions on the ίθ lens 3 (or 4), That is, each region 31, 32 (or 41, 42, 43) is provided with a different optical parameter set relative to the different positions or angles of the incident laser beam, so that f Θ lens 3 or 4 different regions The plurality of optical faces are respectively composed of an optimal optical parameter group, thereby forming a multi-section optical surface (multi-sections optica) l surface ) ίθ Lens 3 or 4 can achieve high-quality assembly quality and high performance broom. Referring again to Figures 5, 5A, 6, and 6A, the f-Θ lens 3 of a 2-section optical surface is taken as an example, due to the optical surface of the first region 31 and the second region 32. It is composed of different optical parameter sets, so that the optical surface intersections of the first region 31 and the second region 32 may have different degrees of surface faults, wherein the edge ends of the f Θ lens are generated. The maximum difference is as shown in Figure 5A or 6A. For the possible difference 5, the simulated curve fitting can be performed first, and the surface of the simulated 125881 can be corrected. Optical simulation to determine an optimal continuation surface profile 51, and then use ultra-precise machining, such as using a digital control (NC) program to set the tool path (SAG value), In order to complete a multi-section optical surface f Θ lens forming mold, the optical surface interface of two different regions in the forming mold has the best smooth continuous surface. (Continuing surface profile), and become ί Θ lens mold of the injection molding (injection molding) of the mold. The invention also has a multi-section optical surface structure, which can overcome the structural design problem that only one single parameter group is used for each optical surface of the conventional f Θ lens, and a preferred implementation is adopted. For further explanation, please refer to Figures 7 and 8, which are f-lens lenses 3 with a 2-sections optical surface, and optical regions of each region, including optical faces 311, 312 of the first region. And the optical surfaces 321 and 322 of the second region are respectively composed of a set of parameter groups as four sets of parameter groups as shown in FIG. 7; and the quality of the imaging spot is as shown in FIG. 8 at the upper left and lower right. The light spot 81 shown by each of the five 1 coffee circle diameters is the image quality of the f lens of the present invention, and the light spots of the four 1 〇〇 μιη diameter circles shown in the lower left and upper right sides are The imaging quality of the conventional lens is compared. It can be seen that the imaging spot quality of the f Θ lens of the present invention is obviously superior to that of the conventional ί θ lens. Referring again to FIG. 9, the lens of the present invention having a multi-sections optical surface structure comprises the following steps: 〃 1250781 First, the number of regions of the lens, such as 2-sections~n -sections, and for each region, such as the first region (secti〇n 1), the first region (section 2 ) · the nth region (section η), and simulate a set of optimal parameters to form the region The optical surface; the surface error that may occur at the intersection of the optical surfaces of a different area' uses the curved surface curvature and the optical simulation to make the optical surface junction at two different regions. Determine an optimal continuation surf ace profile; ® Re-use ultra-precise machining methods, such as using the digital control (NC) program to set the tool path (SAG value) for machining the mold' Forming a molding die of a multi-section optical surf ace ί θ lens; and using the f Θ lens molding die to perform mold ejection An injection molding process is used to mass produce a f-mirror lens having a multi-section optical surface structure. In summary, the present invention can achieve the desired effects by the above-disclosed structure, and the present invention has not been disclosed in the publication and has not disclosed the use of the novels, advancements, and the like. The drawings and the descriptions of the present invention are merely illustrative of the embodiments of the present invention, and are not intended to limit the embodiments of the present invention; All changes or modifications should be covered in the scope of the patent application below. 12 1250781 [Simple description of the diagram] Fig. 1 is a perspective view of a conventional laser scanning device module. Figure 1A: A top view of the optical path of Figure 1. Figure 1B: A side view of the optical path of Figure 1. Figure 2: The structure of a f-type lens whose optical surface has only a single parameter set. Fig. 3 is a schematic diagram of a light spot that is simulated by a single parameter set using a single parameter set. Fig. 4 is a schematic view showing the division of an embodiment of a 2-sections optical surface of the present invention. Fig. 4A is a schematic view showing the division of a three-section optical surface embodiment of the present invention. Fig. 5 is a structural top view of an embodiment of a 2-sections optical surface of the present invention. Fig. 5A is a cross-sectional view of Fig. 5A-5A in Fig. 5. Figure 6 is a side view of the structure of Figure 5. Fig. 6A is a cross-sectional view taken along line 6A-6A of Fig. 6. Figure 7 is a structural view of an embodiment of a lens of a two-section (2-sections) optical surface of the present invention. Fig. 8 is a schematic diagram of the light spot of the simulation experiment in Fig. 7. (Compared with the light spot of the undivided area) Fig. 9 is a block diagram of the manufacturing method of the f-inch lens of the present invention having a multi-section optical surface. 13 1250781 [Description of main components] Laser scanning device 1 Semiconductor laser 10 Fine hole 11 Collimating mirror 12 Cylindrical mirror 13 Polyh mirror 14 Reflecting surface 15 f Θ Lens 16 Light receiving surface 17 f Θ Lens 2 Optical surface 21 > 22 f-lens 3 dividing line 3a, 4a area 31 area 41, 42, 43 optical surfaces 311, 312, 321 , 322 optical surfaces 411, 412, 421, 422, 431, 432 lag 5 smooth continuous surface type!