200912422 九、發明說明： 【發明所屬之技術領域】 本發明涉及一種透鏡系統，尤其涉及一種用於電子 設備之透鏡糸統。 【先前技術】 近年來，隨著多媒體之發展，對手提電腦與可視電 話以及手機等使用之CCD(Charged Coupled Device)或 CMOS(Complementary Metal Oxide Semiconductor)等固 體成像器件之攝像元件之需求越來越大。而此種需求增 大之本身又要求透鏡系統更進一步之小型化。 另一方面，由於此類固體成像器件如CCD或者 CMOS之工藝技術提高，已經製作出每一晝素只有幾個 微米大小之成像器件，使得系統小型化之同時提高了對 攝像鏡頭之解析度之要求。因此，提供一種具長度小、 光學性能優良且成像品質好之透鏡系統係現今微型攝像 元件之發展方向。'所述長度小係指從透鏡系統之第一面 到成像面之距離（即成像系統之總長）要短。 【發明内容】 有鑒於此，有必要提供一種小型化、成像性能良好 之透鏡系統。 一種透鏡系統，其從物側到成像面依次包括：一具 有負光焦度之第一透鏡，一具有正光焦度之第二透鏡， 一具有負光焦度之第三透鏡，一具有正光焦度之第四透 6 200912422 鏡，一具有負光焦度之第五透鏡，以及一具有正光焦度 之第六透鏡。所述透鏡系統滿足以下條件：TT/f <1.68與 0.3<f/f23<0.4，其中，TT為第一透鏡靠近物側之表面到 系統成像面之距離，f 23為所述第二透鏡及所述第三透鏡 組成之透鏡組合之有效焦距，f為透鏡系統之有效焦距。 條件式TT/f <1.68限制了透鏡系統之總長。條件式 0.3<f/f23<0.4保證了透鏡系統總長與球差及藝差之間之 平衡。滿足上述條件之透鏡系統，具有較小長度，從而 滿足透鏡系統小型化之要求，且該透鏡系統於其長度縮 小之情況下仍保證最終獲取較好圖像品質。 【實施方式】 下面將結合附圖對本發明實施例作進一步之詳細 說明。 請參閱圖1，其為本發明實施例所提供之透鏡系統 100。該透鏡系統100從物侧到成像面依次包括：一具有 負光焦度之第一选鏡10, 一具有正光焦度之第二透鏡 20, 一具有負光焦度之第三透鏡30, 一具有正光焦度之 第四透鏡40, 一具有負光焦度之第五透鏡50, 一具有正 光焦度之第六透鏡60。 當該透鏡系統100用於成像時，來自被攝物之光線 從物侧方向入射所述透鏡系統100並依次經過所述第一 透鏡10、第二透鏡20、第三透鏡30、第四透鏡40、第 五透鏡50及第六透鏡60，最終會聚到一成像面90上， 藉由將CCD或CMOS等影像感測裝置設於所述成像面 7 200912422 90處，即可獲取該被攝物之像。 為實現小型化及高成像性能之要求，該透鏡系統 100滿足以下條件式： (1) TT/f<1.68 與 (2) 0.3<f/f23<0.4。 其中，TT為第一透鏡靠近物侧之表面到系統成像 面90之距離，f23為所述第二透鏡20及所述第三透鏡30 組成之透鏡組合之有效焦距，f為透鏡系統100之有效 焦距。條件式（1)限制了透鏡系統100之總長。條件式（2) 保證了透鏡系統100總長與球差及彗差之間之平衡。 優選地，第六透鏡60還滿足以下條件： (3) l<f/f6<1.2。 其中，f6為所述第六透鏡之焦距。條件式（3)滿足透 鏡系統100對總光焦度之要求，同時使透鏡系統100更 接近遠心（Telecentric)成像系統，增強外界光感測器之收 光率，保證了透鏡系統100總長與像差之間之平衡。 為了更好消除透鏡系統100之色差，尤其係倍率色 差，第二透鏡20、第三透鏡30及第四透鏡40還滿足以 下條件： (4) Vd2>Vd3 與 (5) Vd4>Vd5。 其中，Vd2為第二透鏡20之阿貝數，Vd3為第三透 鏡30之阿貝數，Vd4為第四透鏡40之阿貝數，Vd5為 第五透鏡之阿貝數。條件式（4)、（5)有助於縮小透鏡系統 8 200912422 100之體積，保證透鏡系統100總長與色差之間之平衡。 為保證於第一透鏡10與第二透鏡20之間放置光圈 或快門，同時保證第一透鏡10、第二透鏡20還滿足以 下條件： (6) (^〈DAu/fcOJ。 其中，DA!_2為第一透鏡10與第二透鏡20之軸上 間隔（第一透鏡10之靠像侧面與第二透鏡20靠物侧面之 間之光軸長度）。 所述透鏡系統100還包括一光闌（Aperture stop)70 以及一濾光片80。該光闌70位於第一透鏡10與第二透 鏡20之間，以限制經過第一透鏡10之光線進入第二透 鏡20之光通量，並讓經過第一透鏡10後之光錐能更加 對稱，使透鏡系統100之彗差得以修正。為節約成本， 縮短透鏡系統100之全長，可採用不透光材料塗佈第二 透鏡20物侧表面外圈，充當光闌70。可以理解，光闌 7 0如此設置還有利於縮短透鏡系統之全長。所述濾光片 80位於第六透鏡60與成像面90之間，主要用於濾除進 入透鏡系統100光線中之位於紅外波段之光線。 可以理解，本發明實施例之透鏡系統100之第一透 鏡10、第二透鏡20、第三透鏡30、第四透鏡40、第五 透鏡50及第六透鏡60都採用玻璃製成，保證成像品質 較好之同時，成本相對較低，並且易於實現量產。 下面請參照圖2至圖7，以具體實施例來詳細說明 透鏡系統100。 9 200912422 •. 以下每一實施例中，所述第一透鏡ίο、第二透鏡 . 20、第三透鏡30、第四透鏡40、第五透鏡50及第六透 鏡60之各表面均為球面。 . f:透鏡系統100之有效焦距；FNo: F(光圈）數；2ω : 視場角。 實施例1 該透鏡系統100各光學元件滿足表1之條件，且其 ΤΤ=11.64 毫米（mm) ; f=6.91mm ; f23=19.2939mm ; FNo = 3.19 ; 2ω=560。 表1 透鏡系統100 曲率半徑（mm) 厚度（mm) 折射率 阿貝數 被攝物 無窮大 1000 — — 第一透鏡10靠物 側表面 55.82214 0.52 1.58913 61.135 第一透鏡10靠像 側表面 27.47293 1.3 ---- — 光闌70 無窮大 0.22 — — 第二透鏡20靠物 側表面 3.571711 0.9761735 1.882997 40.7651 第二透鏡20靠像 側表面 -10.97649 0.1 ---- --- 第三透鏡30靠物 側表面 -5.59937 0.52 1.698947 30.1279 第三透鏡30靠像 側表面 3.373019 0.552519 — --- 第四透鏡40靠物 側表面 10.15544 1.23667 1.788001 47.3685 第四透鏡40靠像 側表面 -3.815141 0.7072471 --- --- 第五透鏡50靠物 側表面 -2.661624 0.52 1.592701 35.3101 第五透鏡50靠像 側表面 8.585195 0.9975566 --- --- ίο 200912422 _側表面 第六透鏡60靠像 側表面 濾光片8 0靠物側 _表面_ 光片80靠 表面 9.9103 -11.4479 無窮大 無窮大 1.880943 1.816 46.62 0.4134666 °·8 1.5168 64.16 0.9 該實施例1之透鏡系統100中，其球差、場曲及畸 變分別如圖2到圖4所示。圖2中，分別針對g線（波 長值435.8納米（nm))’ d線（波長值587.6 nin)，c線（波 長值656·3 nm )而觀祭到之球差值。總體而言，實施例 1之透鏡系統100對可見光（波長範圍於4〇〇 nm -700 nm 之間）產生之球差值在（_〇.lmin，〇.lmm)範圍内。圖3中之 S(子午場曲值）與τ(弧矢場曲值）均控制於 (-0.1mm，0.1 mm)範圍内。圖4中之畸變率控制於（_2%，2%) 範圍内。由此可見’透鏡系統100之球差、場曲、畸變 都能被很好校正。 實施例2 . 該透鏡系統100各光學元件滿足表2之條件，且其 f=7_〇98mm ; f23 = 18.8125mm ; FNo=3_19 ; 2ω=53.38。。 表2 透鏡系統100 被攝物 曲率半徑（mm) 厚度（mm) 折射率 阿貝數 無窮大 1000 _ _ 第一透鏡10靠 __物側表面 138 0.515 1.48749 70.4058 第一透鏡10靠 _像側表面 38.5071 1.2933 — --- ___光闌70 無窮大 0.2166 ___ ... 第二透鏡20靠 3.434642 0.9954933 1.90217 40.7651 η 200912422 物側表面 第二透鏡20靠 像側表面 -12.82318 0.1 --- --- 第三透鏡30靠 物側表面 -6.115171 0.515 1.729672 28.6914 第三透鏡30靠 像側表面 3.257676 0.553578 --- --- 第四透鏡40靠 物側表面 8.529067 1.220021 1.743972 44.8504 第四透鏡40靠 像側表面 -3.63408 0.681474 … --- 第五透鏡50靠 物側表面 -2.509925 0.515 1.642602 34.2214 第五透鏡50靠 像側表面 10.56706 0.901031 — --- 第六透鏡60靠 物側表面 10.2255 1.944665 1.8068 45.6199 第六透鏡60靠 像側表面 -10.11677 0.464267 --- … 濾光片80靠物 側表面 無窮大 0.8 1.5168 64.16 濾光片80靠像 側表面 無窮大 0.9 --- --- 該實施例2之透鏡系統100中，其球差、場曲及畸 變分別如圖5到圖.7所示。圖5中，分別針對g線（波 長值435.8nm)，d線（波長值587.6nm)，c線（波長值 656.3nm)而觀察到之球差值。總體而言，實施例2之 透鏡系統100對可見光（波長範圍於400nm-700nm之間） 產生之球差值在（-0.1111111，0.1111111)範圍内。圖6中之3(子 午場曲值）與T(弧矢場曲值）均控制於（-0.1mm,0.1mm)範 圍内。圖7中之畸變率控制於（-2%，2%)範圍内。由此可 見，透鏡系統100之球差、場曲、畸變都能被很好校正。 所述透鏡系統100具有較小長度，從而滿足透鏡系 12 200912422 -.統小型化之要求，且該透鏡系統於其長度縮小之情況下 , 仍保證透鏡糸統總長與像差之間之平衡，提南最終獲取 圖像之品質。 綜上所述，本發明確已符合發明專利要件，爰依法提出 專利申請。惟，以上所述者僅為本發明之較佳實施方式，舉 凡熟悉本案技藝之人士，於援依本案發明精神所作之等效修 飾或變化，皆應包含於以下之申請專利範圍内。 【圖式簡單說明】 r 圖1為本發明實施例提供之一種透鏡系統示意圖。 圖2為本發明實施例1之透鏡系統之球差圖。 圖3為本發明實施例1之透鏡系統之場曲圖。 圖4為本發明實施例1之透鏡系統之畸變圖。 圖5為本發明實施例2之透鏡系統之球差圖。 圖6為本發明實施例2之透鏡系統之場曲圖。 圖7為本發明實施例2之透鏡系統之畸變圖。 【主要組件符號說明】 透鏡系統 100 第一透鏡 10 第二透鏡 20 第三透鏡 30 第四透鏡 40 第五透鏡 50 第六透鏡 60 光闌 70 濾光片 80 成像面 90 13200912422 IX. Description of the Invention: [Technical Field] The present invention relates to a lens system, and more particularly to a lens system for an electronic device. [Prior Art] In recent years, with the development of multimedia, there has been an increasing demand for imaging elements of solid-state imaging devices such as CCD (Charged Coupled Device) or CMOS (Complementary Metal Oxide Semiconductor) used in portable computers and videophones and mobile phones. Big. This increase in demand itself requires further miniaturization of the lens system. On the other hand, due to the improvement of the process technology of such solid-state imaging devices such as CCD or CMOS, imaging devices having a size of only a few micrometers per pixel have been fabricated, which makes the system smaller while improving the resolution of the camera lens. Claim. Therefore, a lens system having a small length, excellent optical performance, and good image quality is a development direction of today's miniature image pickup elements. 'The small length means that the distance from the first side of the lens system to the imaging surface (i.e., the total length of the imaging system) is short. SUMMARY OF THE INVENTION In view of the above, it is necessary to provide a lens system that is miniaturized and has excellent imaging performance. A lens system comprising, in order from the object side to the imaging surface, a first lens having a negative power, a second lens having a positive power, a third lens having a negative power, and a positive optical focus The fourth through 6 200912422 mirror, a fifth lens with negative power, and a sixth lens with positive power. The lens system satisfies the following conditions: TT / f < 1.68 and 0.3 < f / f23 < 0.4, wherein TT is the distance from the surface of the first lens near the object side to the imaging surface of the system, and f 23 is the second The effective focal length of the lens combination of the lens and the third lens, f is the effective focal length of the lens system. The conditional formula TT/f < 1.68 limits the total length of the lens system. The conditional formula 0.3<f/f23<0.4 guarantees a balance between the total length of the lens system and the spherical aberration and the difference in art. A lens system that satisfies the above conditions has a small length to meet the requirements for miniaturization of the lens system, and the lens system ensures a final image quality with a reduced length. [Embodiment] Hereinafter, embodiments of the present invention will be further described in detail with reference to the accompanying drawings. Please refer to FIG. 1, which is a lens system 100 according to an embodiment of the present invention. The lens system 100 includes, from the object side to the imaging surface, a first selection mirror 10 having a negative power, a second lens 20 having a positive power, and a third lens 30 having a negative power. A fourth lens 40 having a positive power, a fifth lens 50 having a negative power, and a sixth lens 60 having a positive power. When the lens system 100 is used for imaging, light from a subject is incident on the lens system 100 from the object side direction and sequentially passes through the first lens 10, the second lens 20, the third lens 30, and the fourth lens 40. The fifth lens 50 and the sixth lens 60 are finally concentrated on an imaging surface 90, and the image sensing device such as CCD or CMOS is disposed on the imaging surface 7 200912422 90 to obtain the object. image. To achieve miniaturization and high imaging performance, the lens system 100 satisfies the following conditional formula: (1) TT/f < 1.68 and (2) 0.3 < f/f23 < 0.4. Wherein, TT is the distance from the surface of the first lens near the object side to the imaging surface 90 of the system, f23 is the effective focal length of the lens combination of the second lens 20 and the third lens 30, and f is effective for the lens system 100. focal length. Conditional formula (1) limits the total length of lens system 100. Conditional formula (2) guarantees a balance between the total length of the lens system 100 and the spherical aberration and coma. Preferably, the sixth lens 60 further satisfies the following condition: (3) l <f/f6 < 1.2. Where f6 is the focal length of the sixth lens. The conditional expression (3) satisfies the requirements of the lens system 100 for the total power, and at the same time brings the lens system 100 closer to the telecentric imaging system, enhances the light collection rate of the external light sensor, and ensures the total length and image of the lens system 100. The balance between the differences. In order to better eliminate the chromatic aberration of the lens system 100, especially the chromatic aberration of magnification, the second lens 20, the third lens 30, and the fourth lens 40 satisfy the following conditions: (4) Vd2 > Vd3 and (5) Vd4 > Vd5. Wherein, Vd2 is the Abbe number of the second lens 20, Vd3 is the Abbe number of the third lens 30, Vd4 is the Abbe number of the fourth lens 40, and Vd5 is the Abbe number of the fifth lens. Conditional formulas (4) and (5) help to reduce the volume of the lens system 8 200912422 100, ensuring a balance between the total length of the lens system 100 and the chromatic aberration. In order to ensure that an aperture or a shutter is placed between the first lens 10 and the second lens 20, it is ensured that the first lens 10 and the second lens 20 also satisfy the following conditions: (6) (^<DAu/fcOJ. Among them, DA!_2 The axis of the first lens 10 and the second lens 20 are spaced apart (the optical axis length between the image side of the first lens 10 and the object side of the second lens 20). The lens system 100 further includes an aperture ( Aperture stop 70 and a filter 80. The aperture 70 is located between the first lens 10 and the second lens 20 to limit the light flux entering the second lens 20 through the first lens 10 and pass through the first The light cone behind the lens 10 can be more symmetrical, so that the coma of the lens system 100 can be corrected. To save cost and shorten the total length of the lens system 100, the outer surface of the object side surface of the second lens 20 can be coated with an opaque material to serve as The aperture 70. It can be understood that the arrangement of the aperture 70 is also advantageous for shortening the total length of the lens system. The filter 80 is located between the sixth lens 60 and the imaging surface 90, and is mainly used for filtering out light entering the lens system 100. The light in the infrared band. The first lens 10, the second lens 20, the third lens 30, the fourth lens 40, the fifth lens 50, and the sixth lens 60 of the lens system 100 of the embodiment of the present invention are all made of glass to ensure good imaging quality. At the same time, the cost is relatively low, and mass production is easy to implement. Referring now to Figures 2 to 7, the lens system 100 will be described in detail with reference to a specific embodiment. 9 200912422 • In each of the following embodiments, the first lens Each surface of the second lens 20, the third lens 30, the fourth lens 40, the fifth lens 50, and the sixth lens 60 is a spherical surface. f: effective focal length of the lens system 100; FNo: F (aperture) Number; 2ω: field of view. Example 1 The optical elements of the lens system 100 satisfy the conditions of Table 1, and their ΤΤ = 11.64 mm (mm); f = 6.91 mm; f23 = 19.2939 mm; FNo = 3.19; 2ω = 560. Table 1 Lens system 100 Curvature radius (mm) Thickness (mm) Refractive index Abbe number object infinity 1000 — — First lens 10 object side surface 55.82214 0.52 1.58913 61.135 First lens 10 image side surface 27.47293 1.3 ---- — 光阑70 Infinity 0.22 — The second lens 20 is on the object side surface 3.571711 0.9761735 1.882997 40.7651 The second lens 20 is on the image side surface - 10.97649 0.1 ---- -- The third lens 30 is on the object side surface - 5.59937 0.52 1.698947 30.1279 The third lens 30 is on the image side Surface 3.373019 0.552519 — --- Fourth lens 40 object side surface 10.15544 1.23667 1.788001 47.3685 Fourth lens 40 image side surface -3.815141 0.7072471 --- --- Fifth lens 50 body side surface -2.661624 0.52 1.592701 35.3101 Five lens 50 image side surface 8.585195 0.9975566 --- --- ίο 200912422 _ side surface sixth lens 60 image side surface filter 80 0 object side _ surface _ light sheet 80 surface 9.9103 -11.4479 infinity infinity 1.880943 1.816 46.62 0.4134666 °·8 1.5168 64.16 0.9 The spherical aberration, field curvature and distortion of the lens system 100 of the first embodiment are as shown in Figs. 2 to 4, respectively. In Fig. 2, the g-line (wavelength value 435.8 nanometers (nm))' d line (wavelength value 587.6 nin) and the c-line (wave length value 656·3 nm) are observed for the spherical difference. In general, the lens system 100 of Embodiment 1 produces a spherical difference in visible light (wavelength ranging from 4 〇〇 nm to 700 nm) in the range of (_〇.lmin, 〇.lmm). In Fig. 3, S (meridian curvature value) and τ (radial field curvature value) are both controlled within (-0.1 mm, 0.1 mm). The distortion rate in Figure 4 is controlled in the range of (_2%, 2%). It can be seen that the spherical aberration, field curvature and distortion of the lens system 100 can be well corrected. Example 2. The optical elements of the lens system 100 satisfy the conditions of Table 2, and f = 7_〇98 mm; f23 = 18.8125 mm; FNo = 3_19; 2ω = 53.38. . Table 2 Lens system 100 Subject radius of curvature (mm) Thickness (mm) Refractive index Abbe number infinity 1000 _ _ First lens 10 by __ object side surface 138 0.515 1.48749 70.4058 First lens 10 by _ image side surface 38.5071 1.2933 — --- ___ 阑 70 infinity 0.2166 ___ ... The second lens 20 depends on 3.346462 0.9954933 1.90217 40.7651 η 200912422 The object side surface second lens 20 depends on the side surface -12.82318 0.1 --- --- The third lens 30 object side surface - 6.115171 0.515 1.729672 28.6914 third lens 30 image side surface 3.257676 0.553578 --- --- fourth lens 40 object side surface 8.529067 1.220021 1.743972 44.8504 fourth lens 40 image side surface -3.63408 0.681474 ... --- Fifth lens 50 on the object side surface - 2.509925 0.515 1.642602 34.2214 Fifth lens 50 image side surface 10.56706 0.901031 — --- Sixth lens 60 object side surface 10.2255 1.944665 1.8068 45.6199 Sixth lens 60 image side surface -10.11677 0.464267 --- ... Filter 80 is infinitely large on the side of the object 0.8 1.5168 64.16 Filter 80 depends on the side surface infinity 0.9 --- --- In the lens system 100 of Embodiment 2, the spherical aberration, curvature of field, and distortion are shown in Fig. 5 to Fig. 7, respectively. In Fig. 5, spherical aberration values were observed for the g line (wavelength value 435.8 nm), the d line (wavelength value 587.6 nm), and the c line (wavelength value 656.3 nm). In general, the lens system 100 of Example 2 produces a spherical aberration value in the visible light (wavelength ranging from 400 nm to 700 nm) in the range of (-0.1111111, 0.1111111). In Fig. 6, 3 (the meridional field curvature value) and T (the sagittal field curvature value) are both controlled within the range of (-0.1 mm, 0.1 mm). The distortion rate in Fig. 7 is controlled within the range of (-2%, 2%). It can be seen that the spherical aberration, field curvature and distortion of the lens system 100 can be well corrected. The lens system 100 has a small length to meet the requirements of the lens system 12 200912422 - and the lens system ensures the balance between the total length and the aberration of the lens system when the length thereof is reduced. Timan finally gets the quality of the image. In summary, the present invention has indeed met the requirements of the invention patent, and has filed a patent application according to law. The above description is only the preferred embodiment of the present invention, and equivalent modifications or variations made by those skilled in the art of the present invention should be included in the following claims. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram of a lens system according to an embodiment of the present invention. 2 is a spherical aberration diagram of a lens system according to Embodiment 1 of the present invention. 3 is a field curvature diagram of a lens system according to Embodiment 1 of the present invention. 4 is a distortion diagram of a lens system according to Embodiment 1 of the present invention. Figure 5 is a spherical aberration diagram of a lens system according to Embodiment 2 of the present invention. Figure 6 is a field curvature diagram of a lens system of Embodiment 2 of the present invention. Figure 7 is a distortion diagram of a lens system according to Embodiment 2 of the present invention. [Major component symbol description] Lens system 100 First lens 10 Second lens 20 Third lens 30 Fourth lens 40 Fifth lens 50 Sixth lens 60 Aperture 70 Filter 80 Imaging surface 90 13