TWI398338B - Compensation method for optics mold - Google Patents

Description

光學模仁加工補償方法Optical mold processing compensation method

本發明係有關於一種光學模仁加工補償方法，特別地，本方法依據一光學系統的波前誤差進行補償修正。The invention relates to an optical mold processing compensation method. In particular, the method compensates for the wavefront error of an optical system.

隨著光學工業及光電科技的發展，各式各樣的光學元件與光電系統依不同的需求孕育而生，而光學鏡片即為各種光學系統中不可或缺的零組件之一。除了一般大眾所熟知的天文望遠鏡與攝影機之外，在數位相機、雷射印表機、影印機及投影機等產品上的應用亦已普及化，對光學鏡片的品質與精度的要求亦愈來愈高。With the development of optical industry and optoelectronic technology, a variety of optical components and optoelectronic systems have emerged according to different needs, and optical lenses are one of the indispensable components in various optical systems. In addition to the astronomical telescopes and cameras that are well known to the general public, applications in digital cameras, laser printers, photocopiers, and projectors have also become popular, and the requirements for the quality and precision of optical lenses are increasing. The higher the height.

目前工業用光學鏡片若以使用材料及其製造方法來區分，主要有傳統之玻璃鏡片研磨拋光、模造玻璃鏡片及塑膠射出成形等三大類。傳統鏡片研磨拋光的生產方式以一連串的圓整、成形、研磨、拋光、定心等程序來製作鏡片，不僅加工過程緩慢又涉及相當多的技術，尤其非球面鏡片(aspheric surface)製作更不容易。其次，在製造非球面鏡片方法方面，現今已有業界使用玻璃模造加工及塑膠射出成形(plastic injection molding)技術，且前述兩種技術皆利用模仁及模具以壓模或射出方式而成形。At present, industrial optical lenses are distinguished by the use of materials and their manufacturing methods, and there are three main types of conventional glass lens polishing and polishing, molded glass lenses and plastic injection molding. The traditional lens grinding and polishing method uses a series of rounding, forming, grinding, polishing, centering and other procedures to make the lens. Not only the processing process is slow but also involves a lot of technology, especially the aspheric surface is not easy to make. . Secondly, in the method of manufacturing an aspherical lens, glass molding processing and plastic injection molding technology have been used in the industry, and both of the above techniques are formed by using a mold and a mold by compression molding or injection molding.

還需講述地，目前業界對於非球面鏡片內的模仁加工部分，亦是將非球面鏡片設計參數輸入電腦數值控制(CNC)而對該模仁進行加工，然後輸入至CNC鑽石車床進行修正 加工，以切削出使用者所要的鏡面形狀。It is also necessary to tell the story. At present, for the mold processing part in the aspherical lens, the aspherical lens design parameters are also input into the computer numerical control (CNC) to process the mold core, and then input to the CNC diamond lathe for correction. Machining to cut out the mirror shape desired by the user.

需注意的，一般對鏡片的模仁形狀精度的要求是以鏡片用途來決定，例如低精度的如眼鏡鏡片等，高精度的如光碟機讀取頭等，通常對形狀精度的要求從10 μm到0.1 μm之間甚或更小。因此，在進行模仁設計時，需預先將模造或射出過程中產生的收縮、翹曲、變形、內部應力等效應一併考慮。It should be noted that the requirements for the shape accuracy of the lens are generally determined by the use of the lens, such as low precision such as spectacle lenses, high precision such as CD player read heads, etc., usually requiring a shape accuracy of 10 μm. It is even smaller or smaller between 0.1 μm. Therefore, in the design of the mold core, it is necessary to consider the effects of shrinkage, warpage, deformation, internal stress and the like which are generated during the molding or injection process.

但不幸的事，對於鏡片製作過程中，影響鏡片形狀之因素錯綜複雜，於模仁設計時難以考慮周全，因此針對鏡片的變形狀況進行模仁補償(compensating)修正是玻璃模造與塑膠射出成形等鏡片製作方法中非常重要的工作。傳統做法上，將模造玻璃鏡片或塑膠射出鏡片放置於3D輪廓掃描儀上，利用3D輪廓掃描儀掃描光學鏡片的外形輪廓，再將掃描完的輪廓利用線性迴歸法(Linear regression)求出外型輪廓形狀，以得知鏡片外形計算值與設計值的尺寸誤差，再依此誤差進行模仁補償。此種補償方式對鏡頭(或光學系統)每一個鏡片的2個面都需進行補償處理，且補償效果只能針對單一鏡片，補償過程費時甚久且無法彌補鏡頭組裝所產生的系統誤差。However, unfortunately, in the lens manufacturing process, the factors affecting the shape of the lens are complicated, and it is difficult to consider in the design of the mold. Therefore, the compensation for the deformation of the lens is the lens molding and plastic injection molding. A very important job in the production method. Traditionally, a molded glass lens or a plastic injection lens is placed on a 3D contour scanner, and the contour of the optical lens is scanned by a 3D contour scanner, and the scanned contour is obtained by linear regression. The contour shape is used to know the dimensional error between the calculated value of the lens shape and the design value, and then the mold compensation is performed according to the error. This compensation method requires compensation for the two faces of each lens of the lens (or optical system), and the compensation effect can only be applied to a single lens. The compensation process takes a long time and cannot compensate for the systematic error caused by the lens assembly.

簡明地說，非球面玻璃鏡片的精密度對於光學系統性能有著相當重要的關係，而在模仁加工過程中，如果模仁誤差補償技術做的不好，所生產出來的鏡片與設計值不同，則所組裝的光學系統達不到設計規範的性能。但即使所有鏡片的精度都達到設計要求，光學組裝亦可能產生誤 差，使得光學系統效能降低。In a nutshell, the precision of aspherical glass lenses has a very important relationship with the performance of optical systems. In the process of mold core processing, if the error compensation technology of the mold is not done well, the lenses produced are different from the design values. The assembled optical system does not meet the performance specifications. But even if the accuracy of all lenses meets the design requirements, optical assembly may also produce errors. Poor, resulting in reduced optical system performance.

因此，如有一種模仁加工補償的方法，不只是針對光學元件(鏡片或機構件)進行補償，而是針對光學系統或光學儀器進行補償，則可將光學元件製造誤差與光學系統組裝誤差一併補償處理。Therefore, if there is a method for processing compensation of the mold, not only compensation for the optical element (lens or machine member) but compensation for the optical system or the optical instrument, the optical component manufacturing error and the optical system assembly error can be And compensation processing.

因此本發明的目的就是在提供一種光學模仁加工補償方法，以干涉儀為量測工具，以量測光學鏡頭的波前誤差，其中波前誤差可以用Zernike多項式來表示，為光學系統中鏡片製作誤差與組裝誤差所造成。再將此波前誤差反向輸入光學設計軟體中，利用光學軟體優化功能調整部分鏡片外形參數或鏡片間距等，使得光學系統經部分鏡片外形參數或鏡片間距調整後，其波前與反向輸入之波前誤差吻合，亦即調整光學系統中部分鏡片外形參數或鏡片間距恰可彌補由干涉儀量測所得之波前誤差。如此，便能在調校一個或數個光學元件的情況下使光學系統符合設計要求，改進了以往針對每個光學元件一一進行模仁補償卻又無法保證組裝後光學系統品質的困擾。Therefore, the object of the present invention is to provide an optical mold processing compensation method, using an interferometer as a measuring tool to measure the wavefront error of the optical lens, wherein the wavefront error can be represented by a Zernike polynomial, which is an optical system lens. Manufacturing errors and assembly errors. Then, the wavefront error is reversely input into the optical design software, and the optical software optimization function is used to adjust some lens shape parameters or lens pitches, so that the optical system is adjusted by partial lens shape parameters or lens spacing, and its wavefront and reverse input. The wavefront error is consistent, that is, the adjustment of the lens shape parameters or the lens pitch in the optical system can compensate for the wavefront error measured by the interferometer. In this way, the optical system can be designed to meet the design requirements in the case of adjusting one or several optical components, and the previous method of performing mold compensation for each optical component without guaranteeing the quality of the assembled optical system can be improved.

根據本案之構想，提出一種光學模仁加工補償方法，係包含下列步驟：(a)依據一光學設計結果以取得一光學系統的雛形(prototype)；(b)量測該光學系統的雛形之波前誤差(wavefront error)；(c)將該波前誤差反向(inverse)回饋至一光學設計軟體，並在該光學設計軟體內選定部分設計參 數進行該光學系統優化以得到一組的設計參數；以及(d)根據該組的設計參數與該光學設計結果之差異值進行一光學模仁補正。According to the concept of the present invention, an optical mold processing compensation method is proposed, which comprises the steps of: (a) obtaining an prototype of an optical system according to an optical design result; and (b) measuring a prototype wave of the optical system. Wavefront error; (c) back-feeding the wavefront error back to an optical design software and designing the selected portion of the optical design software The optical system is optimized to obtain a set of design parameters; and (d) an optical mold kernel correction is performed based on the difference between the set of design parameters and the optical design result.

為了更進一步說明本發明為達成預定目的所採取之技術、手段及功效，請參閱以下有關本發明之詳細說明與附圖，相信本發明之目的、特徵與特點，當可由此得一深入且具體之瞭解，然而所附圖式僅提供參考與說明用，並非用來對本發明加以限制者。In order to further illustrate the techniques, means and functions of the present invention in order to achieve the intended purpose, reference should be made to the detailed description of the invention and the accompanying drawings. The drawings are to be considered in all respects as illustrative and not restrictive

傳統模仁誤差補償係針對單一鏡之外形輪廓進行補償，對於機構件尺寸誤差、組裝誤差等光學系統誤差，完全無從補償。單一鏡片的精度再好，還是無法確保光學系統整體性能表現。因此，本發明提出一種光學模仁加工補償方法，係適用在光學系統或光學儀器的基本元件(光學鏡頭)上。以下為本發明之詳細說明。The traditional mold error compensation is compensated for the contour of a single mirror, and there is no compensation for optical system errors such as dimensional error and assembly error of the machine components. The accuracy of a single lens is no better, and the overall performance of the optical system cannot be guaranteed. Therefore, the present invention proposes an optical mold processing compensation method suitable for use in an optical component or a basic component (optical lens) of an optical instrument. The following is a detailed description of the invention.

如第1圖所示，此圖為補償的方法之流程圖。首先，步驟100：依據一光學設計結果以取得一光學系統(光學鏡頭)的雛形(prototype)，其中，前述光學設計結果亦是依使用者的要求下所設定一光學鏡片(以下簡稱鏡片)的參數，如一鏡片之鏡面形狀參數(shape parameter)與表明光學系統中各元件相關位置(將定義一鏡片於該光學系統中所在位置與方向，如該鏡片的位置、該鏡片與另一鏡片之間的間距與該鏡片的傾角等)之參數，以及製造該光學鏡片的材料。再者，為人所熟知的，前述所提及的光學系統的雛形 亦是光學系統之一原型形式(original type)，在建立在新設計光學系統過程中，無可避免地，仍存有不可預期的問題，所以，於開始大量生產該光學系統的產品之前，取得該光學系統的雛形，以能測試(test)及感受(feel)此新設計光學系統的功能是有其必要性的。As shown in Figure 1, this figure is a flow chart of the method of compensation. First, in step 100, a prototype of an optical system (optical lens) is obtained according to an optical design result, wherein the optical design result is an optical lens (hereinafter referred to as a lens) set according to a user's request. Parameters, such as the shape parameter of a lens and the position of each component in the optical system (which will define the position and orientation of a lens in the optical system, such as the position of the lens, the lens and another lens) The parameters of the pitch, the inclination of the lens, etc., and the material from which the optical lens is made. Furthermore, as is well known, the aforementioned prototype of the optical system mentioned It is also an original type of optical system. In the process of building a new design optical system, it is inevitable that there are still unpredictable problems. Therefore, before starting mass production of the optical system products, The prototype of the optical system is necessary to test and feel the function of the newly designed optical system.

步驟110：量測該光學系統的雛形之波前誤差(wavefront error)，在該光學系統的雛形之波前誤差所使用的儀器，於本實施例中，係使用一干涉儀(interferometer)，然而令人理解地，此干涉儀通常用來量測一球面鏡或平面鏡的表面狀況(亦是，平面鏡片與球面鏡片(凸面與凹面)光學元件的表面形狀誤差)，係以準直雷射光穿過標準鏡頭(平面或球面標準鏡頭)後所形成之標準波前(平面波前或球面波前)與鏡片的表面做比較以形成干涉圖形，藉由分析干涉圖形即可得知該鏡片的鏡面表面形狀誤差等狀況。同樣的，也可用來量測該光學系統的波前誤差。如同量測表面形狀誤差般，可分析干涉圖形得知系統波前誤差。此波前誤差為光學系統中各光學元件製造時產生之形狀誤差(鏡面形狀誤差、鏡片偏心與傾斜、光機件尺寸誤差與偏心等)與系統組裝誤差所累積造成的，一般可用Zernike函數來表示。Step 110: Measure the wavefront error of the prototype of the optical system, and the instrument used in the wavefront error of the prototype of the optical system. In this embodiment, an interferometer is used. Comprehensibly, the interferometer is typically used to measure the surface condition of a spherical or planar mirror (also, the surface shape error of the planar lens and the spherical lens (convex and concave) optical components), through collimated laser light passing through The standard wavefront (planar wavefront or spherical wavefront) formed by a standard lens (planar or spherical standard lens) is compared with the surface of the lens to form an interference pattern, and the mirror surface shape of the lens can be known by analyzing the interference pattern. Error and other conditions. Similarly, it can also be used to measure the wavefront error of the optical system. As with the measurement of the surface shape error, the interference pattern can be analyzed to know the system wavefront error. This wavefront error is caused by the shape error (mirror shape error, lens eccentricity and tilt, optical component size error and eccentricity) generated by the optical components in the optical system and system assembly errors. Generally, the Zernike function can be used. Said.

步驟120：將該光學系統的雛形之該波前誤差反向回饋(negative feedback)至如Zemax、Code－V或OSLO此類型的一光學設計軟體來作分析(亦是將取得的Zernike函數輸入至該光學設計軟體內)，並在該光學設計軟體內選定多個設計參數進行該光學系統優化(optimization)以得到一組的設 計參數，而在選定多個設計參數方面為多個鏡片形狀參數及多個鏡片位置參數，其中前述鏡片形狀參數為該等鏡片的曲率半徑(radius)、非球面(aspheric)係數、該鏡片之厚度。前述鏡片位置參數為定義該等鏡片於該光學系統中所在位置與方向之參數，如該鏡片位置、該鏡片與另一鏡片之間的間距與該鏡片的傾角等。如第2A圖及第2B圖所示，利用此光學軟體優化功能調整該光學系統中一個或數個鏡片之設計參數，使補償後的光學系統之波前恰吻合該光學系統的雛形之反向波前誤差，以補償原光學系統因製作、組裝所累積的誤差。Step 120: Negative feedback of the wavefront error of the prototype of the optical system to an optical design software such as Zemax, Code-V or OSLO for analysis (also inputting the obtained Zernike function to The optical design software), and selecting a plurality of design parameters in the optical design software to perform the optical system optimization to obtain a set of settings Calculating parameters, and selecting a plurality of lens shape parameters and a plurality of lens position parameters in selecting a plurality of design parameters, wherein the lens shape parameter is a radius of curvature, an aspheric coefficient, or a lens of the lenses thickness. The aforementioned lens positional parameters are parameters that define the position and orientation of the lenses in the optical system, such as the position of the lens, the spacing between the lens and another lens, the inclination of the lens, and the like. As shown in Figures 2A and 2B, the optical software optimization function is used to adjust the design parameters of one or several lenses in the optical system, so that the wavefront of the compensated optical system coincides with the reversal of the prototype of the optical system. Wavefront error to compensate for errors accumulated in the original optical system due to fabrication and assembly.

步驟130：根據該組的設計參數與該光學設計結果之差異值以進行一光學模仁補正。Step 130: Perform an optical mold kernel correction according to the difference between the design parameters of the group and the optical design result.

而在步驟130中，在對該光學模仁進行補正後，若補正不佳，回至步驟120，以得到另一組的設計參數，進行進一步光學模仁補正。In step 130, after correcting the optical mold, if the correction is not good, the process returns to step 120 to obtain another set of design parameters for further optical mold compensation.

最後，還需提及的，在步驟120中所選用的多個設計參數的選項中可為多個鏡片形狀參數(shape parameter)及多個鏡片位置參數之一或其兩種參數組合。Finally, it should also be mentioned that among the options of the plurality of design parameters selected in step 120 may be one of a plurality of lens shape parameters and a plurality of lens position parameters or a combination of the two parameters.

以上所述係利用較佳實施例詳細說明本發明，而非限制本發明的範圍，本案得由熟習此技術之人士任施匠思而為諸般修飾，然皆不脫本案申請專利範圍所欲保護者。The above is a detailed description of the present invention, and is not intended to limit the scope of the present invention. The present invention is modified by those skilled in the art, and is not intended to be protected by the scope of the patent application. By.

100‧‧‧依據一光學設計結果以取得一光學系統的雛形(prototype)100‧‧‧According to an optical design result to obtain the prototype of an optical system

110‧‧‧量測該光學系統的雛形之波前誤差(wave front error)110‧‧‧Measure the wavefront error of the prototype of the optical system

120‧‧‧將該波前誤差反向(inverse)回饋至一光學設計軟體，並在該光學設計軟體內選定部分設計參數進行該光學系統優化，使該光學系統之波前與反向輸入之波前誤差相 吻合，以得到一組的設計參數 以及120‧‧‧ Inverting the wavefront error back to an optical design software, and selecting a part of the design parameters in the optical design software to optimize the optical system, so that the wavefront and the reverse input of the optical system Wavefront error phase Match to get a set of design parameters as well as

130‧‧‧根據該組的設計參數與該光學設計結果之差異值進行一光學模仁補正130‧‧‧An optical model correction based on the difference between the design parameters of the group and the optical design results

第1圖係繪示本發明之光學模仁加工補償方法之流程 圖。 第2A圖及第2B圖係分別繪示於一光學系統的雛形及一光學設計中輸入反向波前誤差之示意圖。Figure 1 is a flow chart showing the processing method of the optical mold processing of the present invention. Figure. 2A and 2B are schematic diagrams showing the input reverse wavefront error in the prototype of an optical system and an optical design, respectively.

100‧‧‧依據一光學設計結果以製作一光學系統的雛形(prototype)100‧‧‧Prototype of an optical system based on an optical design result

110‧‧‧量測該光學系統的雛形之波前誤差(wave front error)110‧‧‧Measure the wavefront error of the prototype of the optical system

120‧‧‧將該波前誤差反向(inverse)回饋至一光學設計軟體，做為光學系統優化目標，並在該光學設計軟體內選定部分設計參數為可變動參數進行該光學系統優化以得到一 組波前與優化目標吻合之光學系統 以及120‧‧‧ Inverting the wavefront error back to an optical design software as an optical system optimization target, and selecting a part of the design parameters in the optical design software as a variable parameter to optimize the optical system to obtain One Optical system in which the wavefront is matched with the optimization target as well as

130‧‧‧根據優化結果中所變動的設計參數與該光學設計結果之設計參數差異值進行一光學模仁補正130‧‧‧According to the difference between the design parameters of the optimization results and the design parameters of the optical design results, an optical model correction

Claims (6)

一種光學模仁加工補償方法，該方法包含：(a)依據一光學設計結果以取得一光學系統的雛形(prototype)，其中該雛形包含至少兩個光學元件和機構件；(b)量測該光學系統的雛形之波前誤差(wavefront error)；(c)將該波前誤差反向回饋(negative feedback)至一光學設計軟體，並在該光學設計軟體內選定多個設計參數進行該光學系統優化(optimization)，使該光學系統之波前與一反向輸入之波前誤差相吻合，以得到一組的設計參數；以及(d)根據該組的設計參數與該光學設計結果之差異值以進行一光學模仁補正。 An optical mold processing compensation method, the method comprising: (a) obtaining an optical system prototype according to an optical design result, wherein the prototype comprises at least two optical components and machine components; (b) measuring the prototype Wavefront error of the prototype of the optical system; (c) negative feedback of the wavefront error to an optical design software, and selecting a plurality of design parameters for the optical system in the optical design software Optimizing to match the wavefront of the optical system with the wavefront error of an inverse input to obtain a set of design parameters; and (d) the difference between the design parameters of the set and the optical design result To perform an optical mold repair. 如申請專利範圍第1項所述之方法，其中該光學系統為一鏡頭。 The method of claim 1, wherein the optical system is a lens. 如申請專利範圍第1項所述之方法，其中於步驟(c)中，該等設計參數為多個鏡片形狀參數(shape parameter)及多個鏡片之位置參數之一或其兩種參數組合。 The method of claim 1, wherein in the step (c), the design parameters are one of a plurality of lens shape parameters and positional parameters of the plurality of lenses or a combination of the two parameters. 如申請專利範圍第3項所述之方法，其中該等鏡片形狀參數為該等鏡片之曲率半徑(radius)、非球面(aspheric)係數及該鏡片之厚度。 The method of claim 3, wherein the lens shape parameters are a radius of curvature of the lenses, an aspheric coefficient, and a thickness of the lens. 如申請專利範圍第3項所述之方法，其中該等鏡片位置參數為定義該等鏡片於該光學系統中所在位置與方 向之參數，如該鏡片位置、該鏡片與另一鏡片之間的間距與該鏡片的傾角等。 The method of claim 3, wherein the lens positional parameters define a position and a square of the lens in the optical system. Parameters such as the position of the lens, the spacing between the lens and the other lens, the angle of inclination of the lens, and the like. 如申請專利範圍第3項所述之方法，其中於步驟(d)，該光學模仁若補正不佳，則回至步驟(c)，繼續進行該光學系統優化，以得到另一組的設計參數。 The method of claim 3, wherein in step (d), if the optical mold is not properly corrected, returning to step (c), the optical system optimization is continued to obtain another set of designs. parameter.