^^065 九、發明說明： 【發明所屬之技術領域】 本發明是有關於一種鏡頭，且特別是有關於一種定焦 鏡頭* … 【先前技術】 近年來，數位相機裝置快速發展，並且趨於輕薄短小 的a又sf ’數位相機上的光學鏡頭設計也就越趨重要。一般 相機鏡頭可分為定焦鏡頭與變焦鏡頭，定焦鏡頭較為單純 的特性，可以用較低的成本提供數位相機良好的成像品質。 雖然定焦鏡頭設計已經發展了一段時日，但整個定焦 鏡頭的光學系統成本、總長及成像品質，依然有許多的進 步空間。 因此如何降低定焦鏡頭的光學系統成本及總長，並提 供良好的成像品質，使相機裝置可以縮小整體體積與成 本’為目前各廠商所努力之目標。 【發明内容】 因此本發明的目的就是在提供一種定焦鏡頭，用以降 低成本，並提供良好的成像品質。 根據本發明之上述目的，提出一種定焦鏡頭，自物端 到成像端，於光軸上依序包含有第一透鏡組與第二透鏡 組。第一透鏡組為負屈光率，並包含塑膠負透鏡與末端正 透鏡，塑膠負透鏡與末端正透鏡由物端開始，依序設置於 光軸上。此外，塑膠負透鏡具有至少一表面為非球面。第 一透鏡組為正屈光率，並 直有i ,丨、. 塑膠正透鏡。此塑膠正透鏡 -有至J -表面為非球面H 远鏡 -0.5 < 2(7//1(^ < 〇的铬彼 疋“，、鏡頭滿足 /矽<〇的條件’而呵為該第 該第二透鏡組之焦距。 距2G/為 ^照本發明—實施狀定焦鏡頭，由物端到成像端， =軸上依序包含有第—透鏡組與第二透鏡組。第一透鏡^^065 IX. Description of the Invention: [Technical Field] The present invention relates to a lens, and more particularly to a fixed-focus lens* [Prior Art] In recent years, digital camera devices have developed rapidly and tend to The optical lens design on the thin and short a and sf 'digital cameras is becoming more and more important. Generally, the camera lens can be divided into a fixed focus lens and a zoom lens. The fixed focus lens is simpler and can provide good image quality of the digital camera at a lower cost. Although the fixed-focus lens design has been developed for some time, there is still much room for improvement in the optical system cost, overall length and image quality of the fixed-focus lens. Therefore, how to reduce the optical system cost and total length of the fixed-focus lens and provide good image quality, so that the camera device can reduce the overall volume and cost, which is the goal of current manufacturers. SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a fixed focus lens that reduces cost and provides good image quality. According to the above object of the present invention, a fixed focus lens is provided, from the object end to the imaging end, and the first lens group and the second lens group are sequentially included on the optical axis. The first lens group has a negative refractive power and includes a plastic negative lens and a front positive lens. The plastic negative lens and the front positive lens are arranged from the object end, and are sequentially disposed on the optical axis. Further, the plastic negative lens has at least one surface that is aspherical. The first lens group has a positive refractive power and is directly provided with i, 丨, and a plastic positive lens. This plastic positive lens - there is a non-spherical surface of the J - surface H -0.5 < 2 (7 / / 1 (^ < 铬 铬 疋 , 、,, lens meet / 矽 〇 〇 条件 呵 呵 呵 呵 呵The focal length of the second lens group is the same as that of the present invention - the embodiment of the fixed-focus lens, from the object end to the imaging end, the axis includes a first lens group and a second lens group. First lens
自物端至成像端依序包含第-負透鏡與第 :=鏡1二透鏡以正屈光率’自物端至成像端依序 包含第三正透鏡、第四正透鏡與第五負透鏡。且定焦鏡頭 滿足-〇.5<2G//1G/<〇的條件，而1G/為第一透鏡組之焦距，呀 為第二透鏡組之焦距U透鏡與第三正透鏡以塑勝材 料製作，且兩透鏡都有至少一表面為非球面。The self-object end to the imaging end sequentially include a first-negative lens and a first-negative lens, and a second positive lens, a fourth positive lens and a fifth negative lens. . And the fixed focus lens satisfies the condition of -〇.5<2G//1G/<〇, and 1G/ is the focal length of the first lens group, and the focal length U lens and the third positive lens of the second lens group are plastically won. The material is made and both lenses have at least one surface that is aspherical.
藉由將定焦鏡頭的公差敏感度均勻分配，可以提高生 產組立的良率，進而降低整體成本。此外，部份透鏡為塑 膠材質的非球面鏡片，來降低成本及提高成像品質。並配 合光學參數的設計，降低定焦鏡頭的光學系統總長 【實施方式】 本發明之實施例將公差敏感度均勻分配，並將部份透 鏡使用塑膠材質的非球面鏡片，以降低整體成本，提高成 像品質。任何熟習此技藝者，在不脫離本發明之精神和範 圍内，當可變更其中之光學參數與部份透鏡之材質，以符 合實際應用的情形。 本發明實施例之定焦鏡頭由物端至成像端在光轴上依 序包含第一透鏡組與第二透鏡組。當定焦鏡頭裝設於像機 内時’成像端則為相機内的感光元件 光率’且包括有塑膠負透鏡盘末端正透於：鏡、、且為負屈 末端正透鏡由物端開始，依;與 =至少為非球面。第二透鏡組為正 :。塑膠正透鏡’此塑膠正透鏡具有至少一表面為非球 其中，實施例之定焦鏡頭滿足下列條件： -〇.5<2G//ig/<：〇......(1) 而呀為第-透鏡組之焦距，2㈣第二透鏡組之焦距。 此外，第一透鏡組滿足下列條件： -〇.5<Il//z,2/<〇......(2) 其中為塑膠負透鏡之焦距，Z2/為末端正透鏡之焦距。 而第二透鏡組更包含令央正透鏡與成像端負透鏡，且 中央正透鏡設置於塑膠正透鏡與成像端負透鏡之間。第二 透鏡組滿足下列條件： 一 -1.5 < Z,4// L5f < -0,5......(3) 工5/為成像端負透鏡之 其中Z4/為中央正透鏡之焦距 焦距。 為了更加仔細描述各透鏡間的相對關係及作用，請參 照第1圖’為實施例之定焦鏡頭100示意圖。定焦鏡頭刚 由物端160到成像端15〇於光軸17〇上依序包含第一透鏡 組110及第二透鏡組12〇。第一透鏡組11〇為負屈光率由 兩塊透鏡組成’第二透鏡組12G為正屈光率，由三塊透鏡 組成。為了更清楚各透鏡間的相對位置，此處以物端16〇 到成像端150之排列順序為透鏡命名。 第透鏡組110由物端16〇到成像端150依序包含第 ::透鏡112與第二正透鏡丨-其t第-負透鏡X第 W之塑膠負透鏡’第二正透鏡114為末端正透鏡。-一第一透鏡組120由物端16〇到成像端15〇依序包含第 :正透鏡122、第四正透鏡124及第五負透鏡126。其中第 二正透鏡122即為上述之塑膠正透鏡，第四正透鏡124為 中央正透鏡，帛五負透鏡126為成像端負透鏡。 其中第-透鏡組11〇與第二透鏡組12〇必須符合條件 (1)以均勻分配公差敏感度。第―透鏡組㈣藉由負透鏡與 正透鏡互相搭配以校正色收差，第一負透鏡114設計為非 球面以橋正像差，且第一透鏡組110之透鏡U2與114焦 距符合條件（2)。而第二透鏡組12〇中的第四正透鏡124與 第五負透鏡126可相互搭配矯正像差，且第二透鏡組12〇 中第四正透鏡124與第五負透鏡126的焦距符合條件（3)。 此外’疋焦鏡頭100更包括孔徑光闌13〇設置於第— 透鏡組110與第二透鏡組12〇之間。另有濾波器14〇設置 於第二透鏡組120與成像端150之間。 為了顯示定焦鏡頭1〇〇之實用性與優點，將依據上述 條件設計一個實施例，並揭露出此實施例中的各項光學參 數及光學特性圖示。 第一實施例 表1依序列舉定焦鏡頭之第一透鏡組與第二透鏡組於 的各項參數，其中STO.為孔徑光闌130，FS1與FS2為濾 波器140之兩面： 1325065By evenly distributing the tolerance sensitivity of the fixed-focus lens, the yield of the production assembly can be increased, thereby reducing the overall cost. In addition, some of the lenses are aspherical lenses made of plastic to reduce cost and improve image quality. In combination with the design of optical parameters, the total length of the optical system of the fixed-focus lens is reduced. [Embodiment] The embodiment of the present invention uniformly distributes the tolerance sensitivity, and uses aspherical lenses of plastic materials for partial lenses to reduce the overall cost and improve the overall cost. Imaging quality. Anyone skilled in the art can change the optical parameters and the materials of some of the lenses to suit the actual application without departing from the spirit and scope of the present invention. In the fixed focus lens of the embodiment of the present invention, the first lens group and the second lens group are sequentially included on the optical axis from the object end to the imaging end. When the fixed-focus lens is mounted in the camera, the 'imaging end is the light-receiving rate of the photosensitive element in the camera' and includes the end of the plastic negative lens disk that is transparent to the mirror, and the negative-flex end lens starts from the object end. According to; and = at least aspherical. The second lens group is positive :. Plastic positive lens 'This plastic positive lens has at least one surface that is aspherical. The fixed focus lens of the embodiment satisfies the following conditions: -〇.5<2G//ig/<:〇...(1) And the focal length of the first lens group and the focal length of the second lens group of 2 (four). In addition, the first lens group satisfies the following conditions: - 〇.5 <Il / / z, 2 / < 〇 ... (2) where is the focal length of the plastic negative lens, Z2 / is the focal length of the end positive lens . The second lens group further comprises a positive lens and an imaging end negative lens, and the central positive lens is disposed between the plastic positive lens and the imaging end negative lens. The second lens group satisfies the following conditions: -1.5 < Z, 4 / / L5f < -0, 5 (3) 5 / is the imaging end negative lens where Z4 / is the central positive lens Focal length focal length. In order to more closely describe the relative relationship and function between the lenses, reference is made to Fig. 1 which is a schematic view of the fixed focus lens 100 of the embodiment. The fixed focus lens includes the first lens group 110 and the second lens group 12〇 from the object end 160 to the imaging end 15 on the optical axis 17〇. The first lens group 11 〇 has a negative refractive power composed of two lenses. The second lens group 12G is a positive refractive power and is composed of three lenses. In order to better understand the relative position between the lenses, the lens is named here in the order in which the object ends 16 到 to the imaging end 150 are arranged. The first lens group 110 includes, from the object end 16 to the imaging end 150, a :: lens 112 and a second positive lens 丨 - t negative - negative lens X - W plastic negative lens 'second positive lens 114 is the end positive lens. A first lens group 120 includes a positive lens 122, a fourth positive lens 124, and a fifth negative lens 126 from the object end 16 to the imaging end 15 . The second positive lens 122 is the above-mentioned plastic positive lens, the fourth positive lens 124 is a central positive lens, and the fifth negative lens 126 is an imaging end negative lens. The first lens group 11A and the second lens group 12A must satisfy the condition (1) to evenly distribute the tolerance sensitivity. The first lens group (4) is matched with the positive lens by the negative lens to correct the color difference, the first negative lens 114 is designed to be aspherical with the bridge positive aberration, and the focal lengths of the lenses U2 and 114 of the first lens group 110 are in compliance with the condition ( 2). The fourth positive lens 124 and the fifth negative lens 126 of the second lens group 12 可 can be matched with the correction aberration, and the focal lengths of the fourth positive lens 124 and the fifth negative lens 126 of the second lens group 12 符合 are in compliance with the condition. (3). Further, the focus lens 100 further includes an aperture stop 13A disposed between the first lens group 110 and the second lens group 12A. Further, a filter 14 is disposed between the second lens group 120 and the imaging end 150. In order to show the practicality and advantages of the fixed-focus lens, an embodiment will be devised in accordance with the above conditions, and the optical parameters and optical characteristics of the embodiment will be revealed. First Embodiment Table 1 shows the parameters of the first lens group and the second lens group of the focal lens in sequence, wherein STO. is the aperture stop 130, and FS1 and FS2 are the two sides of the filter 140: 1325065
表1 表面序號 曲率半徑（mm) 厚度（mm) 折射率（Nd) 阿貝係數（Vd) 圓雜係數 S11 109 0.8 1.514648 56.963513 -162.1372 S12 3.68 1.6 -0.2059319 S21 30.6 1.6 1.58913 61.3 S22 -15.5 2.6 STO. INF. 0.8 S31 28 1.8 1.514648 56.963513 60.87392 S32 -6.38 0.2 -20.14728 S41 5.58 1.6 1.6968 55.5 S42 -11.03 0.2 S51 16.6 0.8 1.84666 23.8 S52 3.278 3 FS1 INF. 1 1.5168 64.2 FS2 INF. 2.47 IMA. 定焦鏡頭的其他光學特性則列於表2中： 表2 項目 數值 2G//1G/ -0.39918 L\f!L2f -0.4194 LAfILSf -1.1169 9 1325065 系統總長 18.47mm F值 2.857 焦距長度 6mm 最大像高 3.7 mmTable 1 Surface No. Curvature Radius (mm) Thickness (mm) Refractive Index (Nd) Abbe Coefficient (Vd) Round Coefficient S11 109 0.8 1.514648 56.963513 -162.1372 S12 3.68 1.6 -0.2059319 S21 30.6 1.6 1.58913 61.3 S22 -15.5 2.6 STO. INF. 0.8 S31 28 1.8 1.514648 56.963513 60.87392 S32 -6.38 0.2 -20.14728 S41 5.58 1.6 1.6968 55.5 S42 -11.03 0.2 S51 16.6 0.8 1.84666 23.8 S52 3.278 3 FS1 INF. 1 1.5168 64.2 FS2 INF. 2.47 IMA. Other optics for fixed-focus lenses The characteristics are listed in Table 2: Table 2 Item Value 2G//1G/ -0.39918 L\f!L2f -0.4194 LAfILSf -1.1169 9 1325065 System total length 18.47mm F value 2.857 Focal length 6mm Maximum image height 3.7 mm
由表2可知，實施例之定焦鏡頭的2G//1G/參數值為 -0.39918，符合條件（1)。Z1//Z2/參數值為-0.4194，符合條 件（2)。14//15/參數值為-1.1169，符合條件（3)。 此外，第一透鏡組中的第一負透鏡與第二透鏡組中的 第三正透鏡皆為非球面透鏡，非球面透鏡係數方程式如下： r/)2 z= —f———-W + Ah4+Bh6 + Chs+Dhw l + [l-(k + l)c2h2f2As can be seen from Table 2, the 2G//1G/parameter value of the fixed-focus lens of the embodiment is -0.39918, which satisfies the condition (1). The Z1//Z2/ parameter value is -0.4194, which is in accordance with condition (2). The 14//15/parameter value is -1.1169, which satisfies the condition (3). In addition, the first positive lens in the first lens group and the third positive lens in the second lens group are both aspherical lenses, and the aspheric lens coefficient equation is as follows: r/) 2 z= —f———-W + Ah4+Bh6 + Chs+Dhw l + [l-(k + l)c2h2f2
其中z為透鏡的sag值，亦即透鏡面的凹陷度，c為曲 率半徑的倒數，A為透鏡面到光軸間的距離，A：為圓錐係數 (Conic Coefficient)，乂、5、C及D則分別為高階非球面係 數。各非球面的高階非球面係數依序列於表3中： 表3 曲面序號 A Β C D S11 -1.50016X10"4 3.56546 χ ΙΟ-5 -7.024125χ ΙΟ·7 -1.86926 χΙΟ-9 S12 1.19920χ10'3 1.45402x10^ -4.50250 χ ΙΟ"6 1.85992 x1ο-6 S31 5.68833 χ 10'5 2.60156x1ο-4 2.34204 x1ο-6 4.20542 x1ο-6 S32 -6.943 74χ10'3 1.96563 χ 10-3 -2.53741Χ10-4 2.22257 χΙΟ-5 10 1325065 接著請參照第2A與2B圖，此為第一實施例之場曲/ 畸變圖《兩圖中的入射光波長為486奈米（nm)，第2A圖為 場曲圖，圖中的T代表入射光的子午光線（Tangential Ray)， S代表入射光的弧矢光線（Sagittal Ray)，橫座標表示成像點 到理想像面的距離，縱座標為理想像高或入射角度。第2B 圖為畸變圖，橫座標表示成像點到理想點的百分比差，縱 座標為理想像高或入射角度。根據第2A與2B圖所示，實 施例之定焦鏡頭的場曲及畸變情況並不嚴重。 請參照第3A圖至第3F圖。第3A圖至第3F圖分別代 表不同像高下，波長436、486、588與656奈米（nm)的光 扇形（ray fan)圖。其中第3A到3F圖分別為像高0、1.11、 1.85、2_59、3.33及3.7毫米（mm)之處所得之結果。由於具 有子午與弧矢兩面，因此每個像高皆有兩個光扇形圖，一 個對應子午面（PY與EY)，一個對應弧矢面（PX與EX)。根 據光扇形圖的結果，實施例之定焦鏡頭在大部分的狀況 下，其成像誤差值都在可接受的範圍内。 請參照第4圖，此為縱向像差之圖不。在波長為4 3 6、 486、588與656奈米的光線下，實施例之定焦鏡頭具有良 好的成像效果。 請參照第5A與5B圖，為定焦鏡頭之離焦調變轉換函 數（Through Focus MTF)圖。其中，第5A圖中，空間頻 率（Spatial Frequency)設定為 100 lp/mm，第 5B 圖中，空間 頻率設定為200 lp/mm»透過焦點的偏移及相對應的光學轉 換函數（Optical Transfer Function)結果，可得知實施例之定 π 焦鏡頭具有良好的光學分辨率β 實施例之定焦鏡頭將公差敏感度均勻分配，降低成 本°此外’部份透鏡為塑膠材質的非球面鏡面，配合光學 參數的設計’使定焦鏡頭具有良好的成像品質，也同時符 合成本的考量。而且實施例之定焦鏡頭在揭露的光學參數 中，系統總長僅為18.47毫米（mm)，降低實際應用時光學 裝置的光學系統總長。 雖然本發明已以一較佳實施例揭露如上，然其並非用 以限定本發明，任何熟習此技藝者，在不脫離本發明之精 神和範圍内，當可作各種之更動與潤飾，因此本發明之保 護範圍當視後附之申請專利範圍所界定者為準。 【圖式簡單說明】 為讓本發明之上述和其他目的、特徵 '優點與實施例 能更明顯易懂，所附圖式之詳細說明如下： 第1圖係繪示本發明一實施例之定焦鏡頭示意圖。Where z is the sag value of the lens, that is, the concaveness of the lens surface, c is the reciprocal of the radius of curvature, A is the distance from the lens surface to the optical axis, A: is the Conic Coefficient, 乂, 5, C and D is a high-order aspheric coefficient. The high-order aspheric coefficients of each aspheric surface are listed in Table 3: Table 3 Surface number A Β CD S11 -1.50016X10"4 3.56546 χ ΙΟ-5 -7.024125χ ΙΟ·7 -1.86926 χΙΟ-9 S12 1.19920χ10'3 1.45402 X10^ -4.50250 χ ΙΟ"6 1.85992 x1ο-6 S31 5.68833 χ 10'5 2.60156x1ο-4 2.34204 x1ο-6 4.20542 x1ο-6 S32 -6.943 74χ10'3 1.96563 χ 10-3 -2.53741Χ10-4 2.22257 χΙΟ-5 10 1325065 Please refer to the 2A and 2B drawings, which is the field curvature/distortion diagram of the first embodiment. The wavelength of the incident light in the two figures is 486 nm (nm), and the 2A is the field curvature diagram. T represents the Tangential Ray of the incident light, S represents the Sagittal Ray of the incident light, the abscissa represents the distance from the imaged point to the ideal image plane, and the ordinate is the ideal image height or angle of incidence. Figure 2B shows the distortion map. The abscissa indicates the percentage difference from the image point to the ideal point. The ordinate is the ideal image height or angle of incidence. According to Figs. 2A and 2B, the field curvature and distortion of the fixed focus lens of the embodiment are not serious. Please refer to Figures 3A to 3F. Figures 3A through 3F represent ray fan diagrams of wavelengths of 436, 486, 588, and 656 nanometers (nm) at different image heights. The 3A to 3F graphs are the results obtained at heights of 0, 1.11, 1.85, 2_59, 3.33, and 3.7 millimeters (mm), respectively. Since there are two sides of the meridian and the sagittal, each image height has two light sector diagrams, one corresponding to the meridian plane (PY and EY) and one corresponding to the sagittal plane (PX and EX). According to the results of the optical sector diagram, the imaging error of the embodiment of the fixed-focus lens is in an acceptable range under most conditions. Please refer to Figure 4, which is a diagram of longitudinal aberrations. The fixed focus lens of the embodiment has a good imaging effect under light having a wavelength of 4 3 6 , 486, 588 and 656 nm. Please refer to Figures 5A and 5B for the Focus Focus MTF of the fixed-focus lens. In Figure 5A, the spatial frequency is set to 100 lp/mm. In Figure 5B, the spatial frequency is set to 200 lp/mm. » The offset of the transmitted focus and the corresponding optical transfer function (Optical Transfer Function) As a result, it can be known that the fixed π-focus lens of the embodiment has a good optical resolution β. The fixed-focus lens of the embodiment uniformly distributes the tolerance sensitivity and reduces the cost. In addition, the 'partial lens is aspherical mirror surface of plastic material, and cooperates The design of the optical parameters 'has a good focus on the fixed-focus lens, while also meeting the cost considerations. Moreover, in the disclosed optical parameters of the fixed-focus lens of the embodiment, the total length of the system is only 18.47 mm (mm), which reduces the total length of the optical system of the optical device in practical use. Although the present invention has been described above in terms of a preferred embodiment, it is not intended to limit the invention, and it is obvious to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention. The scope of the invention is defined by the scope of the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS In order to make the above and other objects, features, advantages and embodiments of the present invention more obvious, the detailed description of the drawings is as follows: FIG. 1 is a diagram showing an embodiment of the present invention. Schematic diagram of the focal lens.
第2A 圖係繪示本發明第一實施例之變焦鏡頭場之場 變圖FIG. 2A is a diagram showing the field of the zoom lens field according to the first embodiment of the present invention.
第4圖係缯示本發明第一 曲圖。 扇形園。 差圖。 實施例之變焦鏡頭之縱向像 實施例之變焦鏡頭於不 第5 A〜5B圖係續·示本發明第一 1325065 同空間頻率下的離焦調變轉換函數圖。Fig. 4 is a view showing the first graph of the present invention. Fan shaped garden. Difference map. The longitudinal image of the zoom lens of the embodiment is not shown in Figs. 5A to 5B. The first 1325065 of the present invention has a defocus modulation conversion function diagram at the same spatial frequency.
110 :第一透鏡組 114 :第二正透鏡 122 :第三正透鏡 126 :第五負透鏡 140 :濾波器 160 :物端 【主要元件符號說明】 100 :定焦鏡頭 112 :第一負透鏡 120 :第二透鏡組 124 :第四正透鏡 130 :孔徑光闌 150 :成像端 170 :光軸110: first lens group 114: second positive lens 122: third positive lens 126: fifth negative lens 140: filter 160: object end [main element symbol description] 100: fixed focus lens 112: first negative lens 120 : second lens group 124 : fourth positive lens 130 : aperture stop 150 : imaging end 170 : optical axis
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