1271551 玖、發明說明： 【發明所屬之技術領域】 本發明涉及一種中性密度濾光片（Neutral Density Filter，ND Filter)，尤指一種其光譜透射率之平坦度極佳的高濃度的中性密度濾光 【先前技術】 目前，濾光片已經被廣泛應用於投影機、傳統相機、數位相機、手 機、天文望遠鏡等光學器材中，用來使得該等光學器材能夠實現不同 的光學功能。按照遽光片的光譜特性來分，主要有帶通濾光片、截止 濾光片、一向分光濾、光片、反射遽光片及中性密度濾光片。中性密度 濾光片係具有一定的光學密度，其可以減少入射到光學器材之感光膠 片或CCD 4固態感光元件上的光通量，根據其光學密度的不同，其對 光線的阻減作用亦各不相同，但無論其密度大小均不會改變光線的色 彩分佈。例如：在陽光強烈的環境下進行拍照時，要想用大光圈但快 門的速度有限而不夠快時，可以在鏡頭前加裝中性密度濾光片來作減 光之用。 具有固定密度的中性密度濾光片會把所有波長的光線一律減弱，即 在可見光範圍内的所有光譜具有一致的光透射率。有關固定密度的中 性控度濾光片可參閱由美國專利第5,715，103號、第6,842,302B2號及 第6,842,301B2號所揭示的内容。 由美國專利第5,715，1〇3號所揭示的中性密度滤光片是在基板上形 1271551 成一個由多層防反射膜層構成的絕緣膜層，該多層防反射膜層的材料 是從Al2〇3、MgF2和Si〇2中進行選擇的，並且濾光片與空氣接觸的 一側是一 MgF2膜層。 由美國專利第6,842,302B2號及第6,842,301B2號所揭示的中性密 度濾光片是在一個透明的塑膠基板上設置一個鎳鉻合金膜層和一個 Si〇2膜層，並在頂部設置一個膜層，其中該鎳鉻合金膜層含有 90%的金屬鎳和10%的金屬鉻，而Si〇2膜層則充當防反射膜層。然而， 鎳鉻合金膜層和Si〇2膜層相結合共同構成的中性密度濾光片不太穩 定，而且使得相應的製程比較複雜。 上述習知中性密度濾光片的製鍍大都採用Ti02不充足夠的氧氣產 生吸收效應後，和Al2〇3、MgF2相互搭配來完成。但上述習知技術中 並未提及薄膜排列結構是否為對稱。此外，這種製鍍方法不僅製程複 雜，而且必須仔細考慮並計算由於充氧量不足而可能造成Ti02吸收量 的不穩定，而容易對成品的分光效果造成不良影響。 近來’隨著攝影器材的靈敏度的提高，可以通過加重中性密度遽光 片的濃度來進一步降低光的透射率，從而使得光圈開口可以增大。惟， 若以現行的中性密度濾光片對於透射率平坦度的要求是以最大透射率 值（Tmax)與最小透射率值（Tmin)的差值小於平均透射率值（T^g) 乘以百分之八，即（Tmax一Tmin) < Tavg*8%，且入射光的波長範圍 爲400〜700nm來計算時，因高濃度的中性密度濾光片之平均透射率值 (Tavg)相對於低濃度的平均透射率值（Tavg)是比較低，從而使得BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a Neutral Density Filter (ND Filter), and more particularly to a high concentration neutrality in which the flatness of spectral transmittance is excellent. Density Filtering [Prior Art] Currently, filters have been widely used in optical equipment such as projectors, conventional cameras, digital cameras, mobile phones, and astronomical telescopes to enable these optical devices to achieve different optical functions. According to the spectral characteristics of the calendering sheet, there are mainly band pass filters, cut-off filters, one-way split filters, light sheets, reflective calenders and neutral density filters. The neutral density filter has a certain optical density, which can reduce the luminous flux incident on the photosensitive film of the optical device or the CCD 4 solid-state photosensitive element, and its light-reducing effect is different depending on its optical density. The same, but regardless of its density does not change the color distribution of the light. For example, when taking pictures in a strong sunlight, if you want to use a large aperture but the speed of the shutter is limited and not fast enough, you can add a neutral density filter in front of the lens for light reduction. Neutral density filters with a fixed density will attenuate all wavelengths of light, that is, all spectra in the visible range will have consistent light transmission. For a fixed-density neutral-control filter, reference is made to the disclosures of U.S. Patent Nos. 5,715,103, 6,842,302 B2 and 6,842,301 B2. The neutral density filter disclosed in U.S. Patent No. 5,715,1,3 is an insulating film layer formed of a plurality of antireflection film layers on a substrate, the material of which is from Al2. The selected one of 〇3, MgF2 and Si〇2, and the side of the filter in contact with the air is a MgF2 film layer. The neutral density filter disclosed in U.S. Patent Nos. 6,842,302 B2 and 6,842,301 B2 is a nickel-chromium alloy film layer and a Si〇2 film layer on a transparent plastic substrate, and a film is placed on the top. The layer, wherein the nichrome film layer contains 90% metallic nickel and 10% metallic chromium, and the Si〇2 film layer acts as an antireflection film layer. However, the neutral density filter formed by the combination of the Nichrome film layer and the Si〇2 film layer is not stable, and the corresponding process is complicated. The above-mentioned conventional neutral density filter is mostly formed by using Ti02 without sufficient oxygen to generate an absorption effect, and Al2〇3 and MgF2 are matched with each other. However, the above conventional techniques do not mention whether the film arrangement structure is symmetrical. In addition, this plating method is not only complicated in the process, but must be carefully considered and calculated to be unstable due to insufficient oxygenation, which may cause adverse effects on the spectroscopic effect of the finished product. Recently, as the sensitivity of photographic equipment has increased, the transmittance of light can be further reduced by increasing the concentration of the neutral density luminescent sheet, so that the aperture opening can be increased. However, if the current neutral density filter is required for transmittance flatness, the difference between the maximum transmittance value (Tmax) and the minimum transmittance value (Tmin) is less than the average transmittance value (T^g). The average transmittance value of a high concentration neutral density filter (Tavg) is calculated by eight percent, that is, (Tmax - Tmin) < Tavg * 8%, and the wavelength of incident light is in the range of 400 to 700 nm. ) the average transmittance value (Tavg) relative to the low concentration is relatively low, thereby making
1271551 南濃度之（Tmax—Tmin)的差距值相對於低濃度之（Tmax_Tmin) 的差距值要更小。例如，當中性密度濾光片的密度等於〇·8，其平均透 射率值（Tavg)爲15.8時’其平坦度（〔「max—Tmin)的值是小於1.25%; 當中性密度濾光片的密度等於h6，其平均透射率值（Tavg)爲2·5時， 其平坦度（Tmax—Tmin)的值是小於〇 2%。 從上述分析可知，高濃度的中性密度濾光片對於光譜透射率的平坦 度要求相較於低濃度的巾性密錢光片對於光譜透射率的平坦度要求 是更爲嚴格，而習知膜層結構是錄滿足對高紐的巾性密度遽光片 之平坦度要求。故，有必要對f知巾性密錢光狀麟結構進行改 進’以提高目前高濃度的中性密度濾光片之平坦度。 【發明内容】 本發明之主要目的在於提供_種中性密度滤光片，其具有平坦度特 性佳及分光特性佳的特點。 依據本㈣之上述目的’本翻提供—種中性密度濾制1271551 The difference between the south concentration (Tmax-Tmin) and the low concentration (Tmax_Tmin) is smaller. For example, the density of a neutral density filter is equal to 〇·8, and its average transmittance value (Tavg) is 15.8'' flatness ([max_Tmin) value is less than 1.25%; when neutral density filter The density is equal to h6, and when the average transmittance value (Tavg) is 2.5, the value of the flatness (Tmax - Tmin) is less than 〇 2%. From the above analysis, it is known that the high concentration of the neutral density filter is The flatness of the spectral transmittance requires that the flatness of the spectral transmittance is more stringent than that of the low-concentration towel, and the conventional film structure is recorded to satisfy the density of the high density. The flatness requirement of the sheet is required. Therefore, it is necessary to improve the flatness of the light-weight lining structure to improve the flatness of the current high-density neutral density filter. SUMMARY OF THE INVENTION The main object of the present invention is Providing a neutral density filter with good flatness characteristics and good spectral characteristics. According to the above purpose of (4), the present invention provides a neutral density filter.
於基板—側的複數膜層，該制結構爲 0.4M3LmH1.25L0.25H1.25L，复中 w 主 一 ^ A ，、甲Η表不面折射率膜層，其採用了鐵 祕。金作爲麟，L表祕购率顯，該膜騎質爲如2; Μ表 示:折射轉於高折群闕與趣之間財間膜層，財間膜層是 作爲一首層直接鑛製於基板一側矣 <表面上，及mH係該中性密度濾光 片的濃度調整層，m表示一個可 乂根據該中性密度濾光片之濃度與光 譜透射率來確定的數值。 1271551 在上述基板之另一側表面上亦設置有一結 & 〇.4M3LmH1.25L0.25H1.25L 的膜層。 上述臈層結構中的m值與中性密度濾光片的光譜透射率是成等比 例關係，且濃度越大，所述m值就越大，而光譜透射率就越低。光嘈 透射率每降低2.5%，m值便需在原數值上乘以h4。 上述中間膜層的材料折射率是位於1·8〜2·2之間。 ，上述高折射率膜層中的鐵、鎳、鉻的含量分別為··鐵^1%、鎳 # 及鉻 $ 19.2%。 上述基板可以是PET基板、PC或其它塑膠材料、玻璃材料及其它 透明材料。 與本發明之先前技術相比較，本發明中性密度濾光片主要是利用一 折射率位於高折射率膜層與基板之間的中間膜層作爲一首層直接鍍製 於基板表面上，再搭配鐵鎳鉻合金與Si〇2進行堆疊，同時還要對基板 _ 貝加雙面鐘膜，猎此膜層結構可以使得本發明中性密度渡光片之平坦 # 度特性及分光特性均爲極佳。此外，由於在本發明的膜層結構中還採 用了》辰度《周整層，猎此可以使得滤光片在不同的光譜透射率要求下均 可得到極佳的光譜特性。 【實施方式】 請參照第一圖所示，本發明中性密度濾光片1是一高濃度的中性密 度濾光片，其包括有一基板10及鍍製於基板10上的複數膜層20，實 際的實施例中，膜層可以是分別被鍍製在基板的一側或兩側，而為了 8On the substrate-side complex film layer, the structure is 0.4M3LmH1.25L0.25H1.25L, the complex medium w main ^ ^ A, and the nail surface is not surface refractive index film layer, which adopts iron secret. Gold as the Lin, the L table secret rate is obvious, the film riding quality is as 2; Μ means: the refraction turns to the high-fidelity group and the fun between the film layer, the financial film is used as a first layer of direct mineral system On the substrate side 矣 < surface, and mH is the concentration adjustment layer of the neutral density filter, m represents a value which can be determined according to the concentration and spectral transmittance of the neutral density filter. 1271551 A film layer of junction & M.4M3LmH1.25L0.25H1.25L is also disposed on the other side surface of the substrate. The m value in the above layer structure is proportional to the spectral transmittance of the neutral density filter, and the larger the concentration, the larger the m value and the lower the spectral transmittance. For every 2.5% reduction in the transmittance of the aperture, the value of m is multiplied by the original value by h4. The material refractive index of the above intermediate film layer is between 1·8 and 2·2. The content of iron, nickel, and chromium in the high refractive index film layer is respectively ··· iron ^1%, nickel # and chromium $ 19.2%. The substrate may be a PET substrate, a PC or other plastic material, a glass material, and other transparent materials. Compared with the prior art of the present invention, the neutral density filter of the present invention mainly uses an intermediate film layer having a refractive index between the high refractive index film layer and the substrate as a first layer to be directly plated on the surface of the substrate, and then Stacked with iron-nickel-chromium alloy and Si〇2, and also on the substrate _Bega double-sided film, hunting this film structure can make the neutral density of the present invention flatness degree and spectral characteristics are Excellent. In addition, since the entire layer is also used in the film structure of the present invention, this allows the filter to obtain excellent spectral characteristics under different spectral transmittance requirements. [Embodiment] Referring to the first figure, the neutral density filter 1 of the present invention is a high concentration neutral density filter comprising a substrate 10 and a plurality of layers 20 plated on the substrate 10. In an actual embodiment, the film layers may be plated on one or both sides of the substrate, respectively, for
1271551 說明上的簡便，在第一圖中只顯示了基板及其一側的鍍膜。 該中性濾光片1所使用的基板1〇可以是玻璃基板、透明塑膠基板、 壓克力基板或其他透明基板，在本實施例中，基板1〇採用的是pET塑 膠基板，基板10厚度約爲1〇〇μιη。亦可採用pc或其它塑膠材料、玻 璃材料及其它透明材料 上述膜層2〇疋以0.4M3LmH1.25L0.25H1.25L的堆疊方式鐘製於基 板10上，其中Η表示高折射率膜層，其採用了鐵鎳鉻合金作爲膜材， 該Η膜層中鐵、錄、鉻的含量分別為：鐵^1%、錄❹外。及絡 且1H的光學厚度爲0·20ππι，其物理厚度爲4〇nm，中心波長是他 L表示低折射率膜層，該膜層材質爲Si〇2,且1L的光學厚度爲㈣警 其物理厚度爲6〇mn，巾碰長是物啦；及M絲—騎率界於h 膜層與PET基板10之間的中間膜層M，其折射率11等於丨8 在本實施例中，首先是要將-中間膜層料爲首層直接鍛製於基 板H)上’再以低折射賴層L與高折射辅層Η相妓替層疊於該中 間膜層Μ上。藉此形賴2G之詳細結構是顯Ζ間膜層 Μ ’第二膜層爲低折射率L膜層，第三膜層爲高折射率騎/第二 膜層爲低折射率膜層L·，第五膜層爲高折射率膜層Ή， ^ ’第六膜層爲低折 射率膜層L。其中第-膜層（讀）之中間膜層“是物倍的四八 之一波長膜厚鍍製祕板上’·第二膜層（3L)之鱗射顿層L是^ 3倍的四分之一波長膜厚鍍製於第一膜層上；第三 9疋 、層（mH)之高折 射率膜層Η是以m倍的四分之一波長膜厚鍍製於第一 布〜祺層上，該膜層 Ϊ271551 (mH)爲濾、光片的濃度調整層，m值可根據濃度需要及光譜透射率的 要求而定（容後詳述）；第四膜層（1.25L)之低折射率膜層L是以125 倍的四分之一波細厚難於第頌層上；第五膜層（g.25H)之高折 射率膜層Η是以〇·25倍的四分之一波長膜厚鍍製於第四膜層上；第六 膜層（U5L)之低折射麵層L& h25倍的四分之—波長膜賴製 於第五膜層上。按照此方式進行膜層堆疊可以得到光譜特性極佳的中 性密度濾光片。 上述膜層20中之各膜層之膜厚的具體值還可以根據具體要求和應 用環境來確定。 上述膜層2〇中的第三膜層（mH)係濃度調整層，濃度越濃瓜值 越大，而濃度越濃光譜透射率T(%)就越低。丁(％)與m值是成等比麵 係，T(%)每降低2.5%，m值便需在原數值上乘以u。較佳地，可再 輸入膜層設計軟紐化，使得巾賴光更佳地透射率平坦度。 下面以T=10%爲基準來舉例說明兩者間之等比例關係： T=l〇% -> m=0.4 T=7.5% -> m=0.55 T=5〇/〇 m=0.75 T=2.5% m=1.05 T=l% m=1.5 按照光譜透射料T=1G%來設計巾性密度觀#丨之膜層2〇，在 波長範Μ彻〜7GGnm之_能祕到的絲透射轉_線請參照 第二圖所不’而其光譜反射轉性曲線請參照第三圖所示。當然，若 10 1271551 • 样爲其他值時，如：7.5%、5%、2.5%、1%或其他，也可以得 "曰透射率之平坦度雛難的鱗，在此就不將其減曲線一一 呈現。 上述鍍膜的過程可採用一般蒸鍍方法製鍍而成，但在製鐘時可減 製祕件，以調整本發日种性密度濾、光#的分光平坦度。例如，當對 中性讀據光片的第一面進行製鑛後，可以得到（Tmax—TmW < W 馨 AR<2/° ’其中Tmax表示入射光通過中性遽光片之最大透射率值， • Tmm表示人射絲射_光狀最小透辦值，R表示反射率，波 長範圍爲_〜7〇0ffin的辦透射率之平坦度特性曲線示意目，如第四 圖所示。 爲能進-步制比設計值更佳之平坦麟性曲線，在本實施例中還 可以對中性密度遽光片！進行雙面製鍍，便可以得到（丁咖卜丁而^ <0.5%的平坦度特性（如第五圖所示）m/〇的反射率特性（如第 • 六圖所示），即在基板10的另一面亦錢一個與上述膜層20結構招同的 • 膜層，藉由該雙面設計形成互補性的分光光譜，可以得収佳的透射 光平坦度特性。 綜上所述，本發明確已符合發明專利之要件，爰依法提出專利申 請。惟，以上所述者僅爲本發明之較佳實施方式，舉凡熟習本案技從 之人士援依本發明之精神所作之等效修飾或變化，皆涵蓋於後附之申 清專利範圍内。 【圖式簡單說明】 I27l55i 第一圖係本發明中性密度濾光片及其膜層結構的示意圖。 第二圖係依照光譜透射率爲10%來設計中性密度濾光片之膜層結構所 得之在波長範圍爲400〜700nm之間的光譜透射率之特性曲線示意 第三圖係依照光譜透射率爲10%來設計中性密度濾光片之膜層結構所 得之在波長範圍爲400〜700nm之間的光譜反射率之特性曲線示意 圖。 第四圖係當光譜透射率之理論設計值爲10%，並且對中性密度濾光片進 行雙面製鍍後，所得之優化後的光譜實際透射率之平坦度特性示意 圖。 弟五圖係當光譜透射率之理論設計值爲1〇%，並且僅對中性密度濾光片 的第一面進行製鍍後，所得之優化後的光譜實際透射率之平坦度特 性示意圖。 % 鲁 中性费度濾光片1 基板 膜層 20 卑六圖係當光譜透群之理論設計值爲·，並且對巾略麟光片進 行雙面製鍍後’所得之優化後的實際反鱗的碰示音圖。 【主要元件符號說明】 121271551 The description is simple. In the first figure, only the substrate and the coating on one side are shown. The substrate 1 used for the neutral filter 1 may be a glass substrate, a transparent plastic substrate, an acrylic substrate or other transparent substrate. In this embodiment, the substrate 1 is a pET plastic substrate, and the substrate 10 is thick. It is about 1〇〇μιη. The above-mentioned film layer 2 can also be formed on the substrate 10 in a stacking manner of 0.4M3LmH1.25L0.25H1.25L, wherein Η denotes a high refractive index film layer, which can also be made of pc or other plastic materials, glass materials and other transparent materials. The iron-nickel-chromium alloy is used as the membrane material, and the content of iron, recorded and chromium in the ruthenium film layer is respectively: iron ^1%, and recorded. And the optical thickness of 1H is 0·20ππι, its physical thickness is 4〇nm, the center wavelength is L, the low refractive index film layer, the film material is Si〇2, and the optical thickness of 1L is (4) The physical thickness is 6〇mn, the length of the towel is the object; and the M wire-riding rate is the intermediate film M between the h film layer and the PET substrate 10, and the refractive index 11 is equal to 丨8 in this embodiment, First, the intermediate film layer is directly forged onto the substrate H), and then the low refractive layer L and the high refractive auxiliary layer are laminated on the intermediate film layer. The detailed structure by which 2G is formed is the interlayer film layer Μ 'the second film layer is a low refractive index L film layer, and the third film layer is a high refractive index riding/second film layer is a low refractive index film layer L· The fifth film layer is a high refractive index film layer Ή, and the 'sixth film layer is a low refractive index film layer L. The intermediate film layer of the first film layer (reading) is "four times the one-wavelength film thickness plating on the secret layer of the material layer". The second film layer (3L) of the scale layer L is ^3 times four One-wavelength film thickness is plated on the first film layer; the third 9-inch layer (mH) high-refractive-index film layer is plated on the first cloth by a quarter-wave thickness of m times. On the ruthenium layer, the film layer 271551 (mH) is the concentration adjustment layer of the filter and the light sheet, and the m value can be determined according to the concentration requirement and the spectral transmittance requirement (detailed later); the fourth film layer (1.25L) The low refractive index film layer L is harder than the quarter-wave layer of 125 times and is difficult to be on the second layer; the high refractive index film layer of the fifth film layer (g.25H) is a quarter of 25 times. One wavelength film thickness is plated on the fourth film layer; the second film layer (U5L) low refractive surface layer L& h25 times the quarter-wavelength film is applied to the fifth film layer. The film layer stack can obtain a neutral density filter with excellent spectral characteristics. The specific value of the film thickness of each of the film layers 20 can also be determined according to specific requirements and application environments. third The film layer (mH) is a concentration adjustment layer. The higher the concentration, the higher the concentration of the melon, and the higher the concentration, the lower the spectral transmittance T(%). The D (%) and m values are in equal proportion, T (%) For every 2.5% reduction, the m value needs to be multiplied by u in the original value. Preferably, the re-input film design is soft-neutralized to make the transmittance flatness better. The following is based on T=10%. To illustrate the proportional relationship between the two: T=l〇% -> m=0.4 T=7.5% -> m=0.55 T=5〇/〇m=0.75 T=2.5% m=1.05 T= l% m=1.5 According to the spectral transmission material T=1G% to design the towel density view #丨的膜层2〇, in the wavelength range 〜 〜 ~ 7GGnm _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ For the spectrum reflection curve, please refer to the third figure. Of course, if 10 1271551 • other values, such as: 7.5%, 5%, 2.5%, 1% or other, you can also get " The flatness of the flatness of the transmittance is not difficult to be presented here. The process of the above coating can be formed by a general evaporation method, but the secret can be reduced when the clock is formed. To adjust the splitting level of the seed density filter and light # For example, when the first side of the neutral reading light sheet is made ore, it can be obtained (Tmax-TmW < W 馨AR<2/° ' where Tmax represents the maximum incident light passing through the neutral glazing sheet. Transmittance value, • Tmm is the minimum illuminance value of the human ray ray, R is the reflectance, and the flatness characteristic curve of the transmittance of the wavelength range is _~7〇0ffin, as shown in the fourth figure. In order to enable a step-by-step flatness curve that is better than the design value, a neutral density calender can also be used in this embodiment! Double-sided plating can be used to obtain the reflectivity characteristics of m/〇 (as shown in Fig. 6), which is the flatness characteristic of 0.5% flatness (as shown in Fig. 5). On the other side of the substrate 10, a film layer which is similar to the structure of the film layer 20 described above, and a complementary spectral spectrum formed by the double-sided design can obtain a good transmitted light flatness characteristic. The present invention has indeed met the requirements of the invention patent, and the patent application is filed according to law. However, the above is only a preferred embodiment of the present invention, and the equivalent of the person skilled in the art according to the spirit of the present invention. Modifications or variations are included in the scope of the appended patents. [Simplified illustration] I27l55i The first figure is a schematic diagram of the neutral density filter and its film structure of the present invention. The characteristic curve of the spectral transmittance in the wavelength range of 400 to 700 nm obtained by designing the film structure of the neutral density filter is 10%. The third figure is designed to be neutral according to the spectral transmittance of 10%. Membrane structure of density filter A schematic diagram of the characteristic curve of the spectral reflectance in the wavelength range of 400 to 700 nm. The fourth figure is when the theoretical design value of the spectral transmittance is 10%, and after the double-density plating of the neutral density filter The obtained flatness characteristic of the actual transmittance of the spectrum is obtained. The fifth design is when the theoretical design value of the spectral transmittance is 1%, and only the first side of the neutral density filter is plated. , the obtained flatness characteristic of the actual transmittance of the spectrum after the optimization. % Lu Neutrality Filter 1 Substrate Film 20 The sixth design is the theoretical design value of the spectral transmissive group, and After the light sheet is double-sided plated, the resulting actual reverse scale is displayed. [Main component symbol description] 12