TWI485474B - High-contrast polarizing plate and liquid crystal display device - Google Patents

High-contrast polarizing plate and liquid crystal display device Download PDF

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TWI485474B
TWI485474B TW098133669A TW98133669A TWI485474B TW I485474 B TWI485474 B TW I485474B TW 098133669 A TW098133669 A TW 098133669A TW 98133669 A TW98133669 A TW 98133669A TW I485474 B TWI485474 B TW I485474B
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film
polarizing
polarizing plate
liquid crystal
polarizing film
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TW201020631A (en
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Yuichiro Kunai
Kiyoshi Muto
Tomohisa Maeda
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Sumitomo Chemical Co
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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0065—Manufacturing aspects; Material aspects
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/133528—Polarisers

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  • Nonlinear Science (AREA)
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  • Crystallography & Structural Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Polarising Elements (AREA)
  • Liquid Crystal (AREA)

Description

高對比偏光板及液晶顯示裝置 High contrast polarizing plate and liquid crystal display device

本發明係關於清晰顯示之高對比液晶顯示裝置、以及該裝置中所使用之偏光板。 The present invention relates to a high contrast liquid crystal display device which is clearly displayed, and a polarizing plate used in the device.

偏光薄膜係以作為在聚乙烯醇系樹脂薄膜吸附定向有二色性色素之型態而廣受使用。並且，已知有以碘作為二色性色素之碘系偏光薄膜、或以二色性直接染料作為二色性色素之染料系偏光薄膜等。此等偏光薄膜通常係在其單面或雙面藉由以聚乙烯醇系樹脂之水溶液所構成之接著劑而貼合三乙醯基纖維素或環烯烴等透明保護薄膜，以製成偏光板。 The polarizing film is widely used as a form in which a dichromatic dye is adsorbed and oriented on a polyvinyl alcohol-based resin film. Further, an iodine-based polarizing film containing iodine as a dichroic dye or a dye-based polarizing film containing a dichroic direct dye as a dichroic dye is known. These polarizing films are usually laminated on a single or double side with a transparent protective film such as triethylenesulfonyl cellulose or cycloolefin by using an adhesive composed of an aqueous solution of a polyvinyl alcohol resin to form a polarizing plate. .

偏光板係廣泛用於作為液晶顯示裝置用光學零件。液晶顯示裝置係作為液晶電視、電腦用螢幕、筆記型電腦、手機等之顯示畫面而擴大其市場。尤其是手機係不分世代而廣泛普及，其進歩程度為非常明顯。特別是在要求輕量化、薄膜化、降低成本之同時，亦要求顯示品質之提升。此外，最近液晶電視之普及率亦明顯地上升，對於此亦在要求降低成本之同時，也要求顯示品質之提升。 A polarizing plate is widely used as an optical component for a liquid crystal display device. The liquid crystal display device expands its market as a display screen for a liquid crystal television, a computer screen, a notebook computer, a mobile phone, and the like. In particular, mobile phones are widely used regardless of generations, and their degree of entry is very obvious. In particular, while demanding weight reduction, thinning, and cost reduction, display quality is also required. In addition, the popularity of LCD TVs has also increased significantly recently. This is also required to reduce the cost while also requiring an increase in display quality.

在如此之顯示品質中有稱為「對比」之特性，其為如下述式所定義之數值：顯示裝置之對比=(白顯示時之亮度)/(黑顯示時之亮度)在此，亮度係指由市售之亮度計等所測定之明亮程度之指 標，例如可由TOPCON(股)等販售之色彩亮度計(BM-5A)、或分光放射計(SR-UL1)等所測定之值。此等係經施行被稱為視感度(luminosity factor)校正之校正並經施以配合人類眼睛之感度的處理而獲得之數值。關於視感度校正將於後文詳細敘述。對比若高，則黑白顯明而能獲得更清晰之圖像，故在此領域一般係使用於作為可見度(visibility)之指標。 There is a characteristic called "contrast" in such display quality, which is a value defined by the following formula: contrast of display device = (brightness in white display) / (brightness in black display) Here, brightness system Refers to the brightness measured by a commercially available luminance meter, etc. The standard value is, for example, a color luminance meter (BM-5A) or a spectroradiometer (SR-UL1) which can be sold by TOPCON or the like. These are values obtained by performing a process called correction of luminosity factor correction and applying a sensitivity to the sensitivity of a human eye. The opacity correction will be described in detail later. If the contrast is high, the black and white is clear and a clearer image can be obtained, so it is generally used in the field as an indicator of visibility.

就用以使此對比提升之手法之一而言，有使作為液晶顯示裝置之必要構件的偏光板的偏光性能提升之方法。在此，所謂偏光性能主要係指被稱為單體透射率與偏光度之數值，其為如下述式所定義之數值：單體透射率(λ)=0.5×(Tp(λ)+Tc(λ)) 偏光度(λ)=100×(Tp(λ)-Tc(λ))/(Tp(λ)+Tc(λ)) In one of the methods for improving the contrast, there is a method of improving the polarizing performance of a polarizing plate which is an essential member of the liquid crystal display device. Here, the term "polarization performance" mainly refers to a value called a single transmittance and a degree of polarization, which is a value defined by the following formula: single transmittance (λ) = 0.5 × (Tp (λ) + Tc ( λ)) Polarization (λ) = 100 × (Tp(λ) - Tc(λ)) / (Tp(λ) + Tc(λ))

在此，Tp(λ)係以入射之波長λ nm之直線偏光與平行尼科耳鏡(parallel Nicol)的關係而測定之偏光薄膜之透射率(%)，Tc(λ)係以入射之波長λ nm之直線偏光與正交尼科耳鏡(crossed Nicol)的關係而測定之偏光薄膜之透射率(%)，此等皆為以分光光度計進行偏光紫外可見吸收光譜測定所得之測定值。此外，對於依各個波長所求之單體透射率(λ)及偏光度(λ)施行被稱為視感度校正之感度校正者，係稱為視感度校正單體透射率(Ty)及視感度校正偏光度(Py)。關於視感度校正將於後文詳細敘述。Ty、Py係可藉由例如日本分光(股)製之分光光度計(型號：V7100) 等而簡便地測定。 Here, Tp(λ) is the transmittance (%) of the polarizing film measured by the relationship between the linear polarized light of the incident wavelength λ nm and the parallel Nicol, and Tc(λ) is the incident wavelength. The transmittance (%) of the polarizing film measured by the relationship between the linear polarized light of λ nm and the crossed Nicol, which are measured by polarized ultraviolet visible absorption spectrometry by a spectrophotometer. In addition, a sensitivity corrector called visual sensitivity correction is performed for the single transmittance (λ) and the degree of polarization (λ) obtained for each wavelength, and is called a visual sensitivity correction single transmittance (Ty) and a visual sensitivity. Correct the degree of polarization (Py). The opacity correction will be described in detail later. Ty and Py can be spectrophotometers made by, for example, Japan Spectrophotometer (Model: V7100) Equivalent and easy to measure.

至今為止，由於關於偏光板之Py、Ty仍有改善之餘地，故藉由提高Py等而提升偏光板之偏光性能，以提升液晶顯示裝置之對比，但最近在偏光板之偏光性能方面亦已幾乎飽和，也已接近理論上之極限值，故現狀上變成已無法再期望偏光性能之大幅提升。就由V7100所測定之Ty、Py值而言，近年來最佳類型之偏光板之偏光性能為Py=99.996%、Ty=42.5%左右，但實質上難以安定地製造出性能比其更高之偏光板。現狀上係例如若欲提升偏光度則透射率即下降而變暗，相反地，若欲提升透射率則偏光度即下降等兩者難以同時兼顧之情況。 So far, there is still room for improvement in Py and Ty of the polarizing plate. Therefore, the polarizing performance of the polarizing plate is improved by increasing Py or the like to improve the contrast of the liquid crystal display device, but recently, the polarizing performance of the polarizing plate has also been improved. Almost saturated, it is close to the theoretical limit value, so the status quo has become no longer expected to greatly improve the polarization performance. In terms of the Ty and Py values measured by V7100, the polarizing performance of the best type of polarizing plate in recent years is Py=99.996% and Ty=42.5%, but it is substantially difficult to stably produce a performance higher than this. Polarizer. In the current situation, for example, if the degree of polarization is to be increased, the transmittance is lowered and darkened. Conversely, if the transmittance is to be increased, the degree of polarization is lowered, and the like is difficult to achieve at the same time.

然而，另一方面，實際上，對於提升液晶顯示裝置之對比的要求仍然非常高，可說是必須根本性地脫離上述改良方法並依據新穎之思考方式而尋求突破。 On the other hand, however, in practice, the requirements for improving the contrast of liquid crystal display devices are still very high, and it can be said that it is necessary to fundamentally break away from the above-described improved methods and seek breakthroughs in accordance with novel ways of thinking.

本發明之目的係提供具有比以往更高之對比的液晶顯示裝置。此外，本發明之目的係提供用以達成此液晶顯示裝置之偏光板、以及製造該偏光板之方法。 It is an object of the present invention to provide a liquid crystal display device having a higher contrast than in the past. Further, it is an object of the present invention to provide a polarizing plate for achieving the liquid crystal display device and a method of manufacturing the same.

本發明人等為了解決上述課題，追溯「對比」之數值之原理、原則進行精心研究之結果，察覺到在至今為止之以偏光板單品之評估為基準的指標「視感度校正單體透射率或視感度校正偏光度」等之思考方式無法達成更高之高對比化的理由，並發現在理解液晶顯示裝置之發光特性後藉由界定偏光板之各波長之特性即可較現今更為提高液晶 顯示裝置之對比的劃時代新穎方法，因而完成本發明。具體而言，是發現到將背光(back light)之發光波長特性及偏光板之偏光薄膜單體對比(SCR)之波長依存性設為某種特定之關係為非常重要，因而完成本發明。此外，亦成功地研發出具有此等特性之偏光板的製造方法。 In order to solve the above-mentioned problems, the present inventors have traced the results of the principle and principle of the numerical value of the "contrast", and have observed the results of the evaluation of the polarizing plate item to date. Or the way of thinking such as sensitivity correction of the degree of polarization can not achieve a higher degree of contrast, and found that by understanding the characteristics of the wavelength of the polarizing plate after understanding the light-emitting characteristics of the liquid crystal display device, the liquid crystal can be improved more than today. An epoch-making novel method of comparing the devices, thus completing the present invention. Specifically, it has been found that it is very important to set the wavelength dependence of the light-emitting wavelength characteristics of the backlight and the polarization of the polarizing film of the polarizing plate (S CR ) to a specific relationship, and thus the present invention has been completed. In addition, a method of manufacturing a polarizing plate having such characteristics has been successfully developed.

亦即，本發明係一種偏光板，其係含有在聚乙烯醇系樹脂薄膜吸附定向有二色性色素之偏光薄膜的偏光板，其特徵為：前述偏光薄膜之下述式(1)所定義之各波長中之偏光薄膜單體對比(SCR(λ))係滿足下述式(2)及(3)之關係，SCR(λ)=T//(λ)/T⊥(λ)…(1)(在此，T//(λ)=0.5×[Tp(λ)2+Tc(λ)2]/100 T⊥(λ)=Tp(λ)×Tc(λ)/100 Tp(λ)係以入射之波長λ nm之直線偏光與平行尼科耳鏡的關係而測定之偏光薄膜之透射率(%)，Tc(λ)係以入射之波長λ nm之直線偏光與正交尼科耳鏡的關係而測定之偏光薄膜之透射率(%)，該等皆為以分光光度計進行偏光紫外可見吸收光譜測定所得之測定值)。 In other words, the present invention is a polarizing plate comprising a polarizing film in which a polarizing film of a dichroic dye is adsorbed on a polyvinyl alcohol-based resin film, wherein the polarizing film is defined by the following formula (1) The contrast of the polarizing film monomers (S CR (λ)) in each wavelength satisfies the relationship of the following formulas (2) and (3), S CR (λ) = T // (λ) / T ⊥ (λ) (1) (here, T // (λ) = 0.5 × [Tp(λ) 2 + Tc(λ) 2 ] / 100 T ⊥ (λ) = Tp (λ) × Tc (λ) / 100 Tp (λ) is the transmittance (%) of the polarizing film measured by the relationship between the linear polarization of the incident wavelength λ nm and the parallel Nicols, and Tc(λ) is the linear polarization and orthogonality of the incident wavelength λ nm. The transmittance (%) of the polarizing film measured by the relationship of Nico's otoscopes, which are measured values by polarization ultraviolet-visible absorption spectrometry of a spectrophotometer).

[(SCR(550)+SCR(600))/2]≧30,000…(2) [(S CR (550)+S CR (600))/2]≧30,000...(2)

3,000≦SCR(450)<30,000…(3) 3,000≦S CR (450)<30,000...(3)

本發明之偏光板較佳係：在前述偏光薄膜之一面藉由接著劑層而積層有乙酸纖維素系樹脂薄膜，並在另一面藉由接著劑層而積層有環烯烴系樹脂薄膜者；或是在前述偏光薄膜之一面藉由接著劑層而積層有乙酸纖維素系樹脂薄 膜，並在另一面藉由黏著劑層而積層可剝離之自行黏著性防護薄膜者。又，前述接著劑層較佳係由水系接著劑所形成者。 In the polarizing plate of the present invention, a cellulose acetate-based resin film is laminated on one surface of the polarizing film by an adhesive layer, and a cycloolefin-based resin film is laminated on the other surface by an adhesive layer; or a cellulose acetate-based resin layer is laminated on one surface of the polarizing film by an adhesive layer The film is laminated on the other side by a layer of adhesive to form a peelable self-adhesive protective film. Further, the adhesive layer is preferably formed of a water-based adhesive.

此外，本發明之偏光板係在含有背光與液晶單元(liquid crystal cell)之液晶顯示裝置中所使用之偏光板，其中，前述液晶顯示裝置較佳係在僅載置液晶單元於前述背光且將背光予以點亮之狀態下測定的光譜中，藍色之發光波峰波長(Bmax)及紅色之發光波峰波長(Rmax)滿足下述式(4)者。 Further, the polarizing plate of the present invention is a polarizing plate used in a liquid crystal display device including a backlight and a liquid crystal cell, wherein the liquid crystal display device preferably mounts only the liquid crystal cell in the backlight and will In the spectrum measured in a state where the backlight is lit, the blue light emission peak wavelength (Bmax) and the red light emission peak wavelength (Rmax) satisfy the following formula (4).

(Rmax-550)<(550-Bmax)…(4) (Rmax-550)<(550-Bmax)...(4)

此外，本發明亦有關於前述偏光板之製造方法，其特徵為：將薄膜積層於水分率9%以上之偏光薄膜之雙面，並在剛積層後40秒以內，以70℃以上之溫度進行加熱處理。 Further, the present invention relates to a method for producing a polarizing plate, which is characterized in that a film is laminated on both sides of a polarizing film having a moisture content of 9% or more, and is carried out at a temperature of 70 ° C or higher within 40 seconds immediately after lamination. Heat treatment.

再者，本發明亦有關於一種液晶顯示裝置，其係含有背光與液晶單元與前述偏光板之液晶顯示裝置，其特徵為：在僅將液晶單元載置於前述背光且將背光予以點亮之狀態下測定的光譜中，藍色之發光波峰波長(Bmax)及紅色之發光波峰波長(Rmax)滿足下述式(4)。 Furthermore, the present invention also relates to a liquid crystal display device comprising a liquid crystal display device including a backlight and a liquid crystal cell and the polarizing plate, wherein the liquid crystal cell is placed on the backlight and the backlight is illuminated. In the spectrum measured in the state, the blue emission peak wavelength (Bmax) and the red emission peak wavelength (Rmax) satisfy the following formula (4).

(Rmax-550)<(550-Bmax)…(4) (Rmax-550)<(550-Bmax)...(4)

本發明之偏光板，即使其偏光板單體之視感度校正偏光度(Py)或視感度校正單體透射率(Ty)與以往之偏光板相同，當使用於具有背光及液晶單元(彩色濾光片(color filter))之發光波長特性的液晶顯示裝置時，相較於使用 以往之偏光板，本發明可大幅地提升液晶顯示裝置之畫面之對比。 The polarizing plate of the present invention has the same visibility correction degree of polarization (Py) or visual sensitivity correction unit transmittance (Ty) as that of the conventional polarizing plate, and is used for having a backlight and a liquid crystal cell (color filter) A liquid crystal display device having an emission wavelength characteristic of a color filter In the conventional polarizing plate, the present invention can greatly improve the contrast of the screen of the liquid crystal display device.

以下，具體闡述本發明。 Hereinafter, the present invention will be specifically described.

在通常之液晶顯示裝置中，若調查從背光通過液晶單元之彩色濾光片而發射出之光，則並非全波長皆相同，會依波長不同而存在有強弱。此強弱係依據背光之發光光譜與彩色濾光片的設計而決定。 In a typical liquid crystal display device, when light emitted from a backlight through a color filter of a liquid crystal cell is investigated, not all wavelengths are the same, and there is a strong or weak depending on the wavelength. This strength is determined by the illumination spectrum of the backlight and the design of the color filter.

背光係依據類型而以某種程度決定發光光譜之形狀，其形狀係依據種類而不同。例如有：具有第1圖所示之發光光譜的冷陰極螢光燈(Cold Cathode Fluorescent Lamp：CCFL)型者、或具有第2圖所示之發光光譜的發光二極體(Light Emitting Diode：LED)等。由於該等組件之發光原理各為不同，故為光譜形狀亦具有某種程度之特徵。 The backlight determines the shape of the luminescence spectrum to some extent depending on the type, and the shape varies depending on the type. For example, a Cold Cathode Fluorescent Lamp (CCFL) type having an emission spectrum shown in Fig. 1 or a Light Emitting Diode (LED) having an emission spectrum shown in Fig. 2 )Wait. Since the illumination principles of the components are different, the spectral shape also has some degree of characteristics.

此外，另一方面，由於液晶單元之彩色濾光片之設計係在顯示裝置之顏色形成上甚為重要，故各公司之設計有所不同。通常多半係由紅(R)、綠(G)、藍(B)之3色所構成。 Further, on the other hand, since the design of the color filter of the liquid crystal cell is important in the color formation of the display device, the designs of the companies are different. Usually, most of them are composed of three colors of red (R), green (G), and blue (B).

必須注意的是，在藉由背光與液晶單元(彩色濾光片)之組合而製作之光譜中，R、G、B之3色之波峰波長的Rmax、Gmax、Bmax不一定可設計成等間隔。此係顯示裝置之顏色形成上之問題，其原因係源自背光之波長特性與源自彩色濾光片。例如在使用白色LED之手機等中，考慮到顏色形成之觀點、或背光之特性時，則以Bmax為450nm左右、Gmax為550nm左右、Rmax為600nm左右為佳。 It should be noted that in the spectrum produced by the combination of the backlight and the liquid crystal cell (color filter), the Rmax, Gmax, and Bmax of the peak wavelengths of the three colors of R, G, and B are not necessarily designed to be equally spaced. . This is a problem in the color formation of the display device due to the wavelength characteristics of the backlight and the color filter. For example, in the case of a mobile phone using a white LED or the like, in consideration of the viewpoint of color formation or the characteristics of the backlight, Bmax is about 450 nm, Gmax is about 550 nm, and Rmax is about 600 nm.

先敘述Rmax(紅色之發光波峰波長)、Gmax(綠色之發光波峰波長)、Bmax(藍色之發光波峰波長)之定義，雖然如手機等LED背光型者係如第2圖所示為波峰明顯而非常容易分辨，但可見於大型液晶電視等之CCFL型背光亦有如第1圖所示之由微細之複數個波峰構成1色者。Bmax係在波峰位置為380至500nm之間的發光波峰之內，積分面積為最大之波峰。如雜訊般之微細跳躍等不計數為波峰，只要因應需要而進行適當之正規分布近似(normal distribution approximation)等擬合法(fitting method)以決定波峰位置即可。Gmax只要從波峰位置為500至570nm之範圍以同樣方式選擇即可，Rmax只要從波峰位置為570至700nm之範圍以同樣方式選擇即可。 First, the definitions of Rmax (red emission peak wavelength), Gmax (green emission peak wavelength), and Bmax (blue emission peak wavelength) are described, although the LED backlight type such as a mobile phone has a peak as shown in FIG. However, it is very easy to distinguish, but CCFL type backlights which can be seen in large liquid crystal televisions, etc., also have one color composed of a plurality of fine peaks as shown in Fig. 1 . Bmax is within the luminescence peak between 380 and 500 nm at the peak position, and the integrated area is the largest peak. A fine jump such as noise is not counted as a peak, and a fitting method such as a normal distribution approximation may be performed as needed to determine the peak position. Gmax can be selected in the same manner from the range of the peak position of 500 to 570 nm, and Rmax can be selected in the same manner from the range of the peak position of 570 to 700 nm.

在此，導入視感度校正之思考方式。人類眼睛之感度係以約550nm之波長之光為最高，離其愈遠之波長之光的感度會變愈差。考慮此現象者為視感度校正之概念，將第3圖所示之左右對稱之正規分布型之校正曲線配合實際之光譜而計算視感度校正亮度。此校正曲線之波峰係位於550nm之位置，意指此波長之光係對於亮度計或人類眼睛之感度最高，相反地，波長離550nm愈遠，則感度愈降低。例如，若以550nm之視感度校正率作為1.0，則在450nm只有0.04以下之比率，亦即，即使為相同之發光量，450nm之波長之光僅測量為550nm之光之1/25之亮度。 Here, the way of thinking about the sensibility correction is introduced. The sensitivity of the human eye is the highest at a wavelength of about 550 nm, and the sensitivity of the light farther away from it is worse. Considering this phenomenon, the concept of visual sensitivity correction is to calculate the visual sensitivity correction brightness by matching the calibration curve of the left-right symmetric normal distribution type shown in FIG. 3 with the actual spectrum. The peak of this calibration curve is located at 550 nm, meaning that the light of this wavelength is the most sensitive to the luminance meter or the human eye. Conversely, the farther the wavelength is from 550 nm, the lower the sensitivity. For example, when the visual sensitivity correction ratio of 550 nm is 1.0, the ratio of only 0.04 or less at 450 nm, that is, even with the same amount of luminescence, the light of the wavelength of 450 nm is only measured as the luminance of 1/25 of the light of 550 nm.

考慮此等現象而重新觀察背光，從550nm至Bmax之間雖為100nm左右之間隔，但從550nm至Rmax之間僅有50nm 左右之間隔。亦即會成為下述式(4)之關係。 Considering these phenomena and re-observing the backlight, the interval between 550 nm and Bmax is about 100 nm, but only 50 nm from 550 nm to Rmax. The interval between left and right. That is, it will become the relationship of the following formula (4).

(Rmax-550)<(550-Bmax)…(4) (Rmax-550)<(550-Bmax)...(4)

此係意指當測定數值作為亮度時，相較於紅色之光，藍色之光係測量為非常弱。反而言之，比起藍色之波峰，紅色之波峰對亮度之貢獻高出非常多。 This means that when the measured value is used as the brightness, the blue light is measured to be very weak compared to the red light. Conversely, the red peak contributes much more to brightness than the blue peak.

關於此傾向，尤其是在將白色LED等用於背光之手機或PDA等攜帶式用途時，由於在其原理上於波長較長側之波峰會產生限制，故上述式(4)之關係更加明顯之情形為多。然而，即使在使用CCFL等設計之大型TV等情形中，從造色等之觀點而言滿足(4)式者大多為較佳，且有相同之傾向。 With regard to this tendency, especially in portable applications such as a mobile phone or a PDA using a white LED or the like for backlighting, since the peak of the longer wavelength side is limited in principle, the relationship of the above formula (4) is more conspicuous. There are many situations. However, even in the case of using a large TV designed such as CCFL or the like, it is preferable that the formula (4) is satisfied from the viewpoint of coloring or the like, and the same tendency is obtained.

本發明係在具有如上述之背光的液晶顯示裝置所使用之偏光板中，藉由採用考慮波長依存性之設計，即可雖不提升偏光板之Ty或Py，但卻能大幅提升顯示裝置之對比。 According to the present invention, in a polarizing plate used in a liquid crystal display device having a backlight as described above, by adopting a design considering wavelength dependence, although the Ty or Py of the polarizing plate is not raised, the display device can be greatly improved. Compared.

此現象係表示在此等顯示裝置所使用之偏光板中各波長之重要度為不同，在組合於上述背光時，以重視紅色區域之偏光性能者為效率較佳。 This phenomenon indicates that the importance of each wavelength in the polarizing plate used in these display devices is different, and when combined with the backlight, it is preferable to pay attention to the polarizing performance of the red region.

現況之偏光板可說是或多或少具有以關注可見光之全波長區域的形式來追求偏光性能之傾向。尤其是以往作為偏光性能之指標的視感度校正單體透射率或視感度校正偏光度，顧名思義，係為關於視感度校正之數值。此視感度校正亦即如第3圖之曲線。就此指標而言，例如，即使為具有第4圖所示之正交透射率(Tp(λ))之光譜(B、G、R之全波長中具有較一致之正交透射率)的偏光板、或是具有第 5圖所示之正交透射率(Tp(λ))之光譜(G、R之波長下之透射率低且B之波長下之透射率高)的偏光板，亦由於以550nm為中心而對稱地使感度下降，而當施行視感度校正時，兩種情形皆會成為相同之數值。 The current polarizing plate can be said to have a tendency to more or less pursue the polarization performance in the form of focusing on the entire wavelength region of visible light. In particular, the illuminance-corrected single-emission transmittance or the illuminance-corrected polarization degree, which is an index of the polarizing performance, is a numerical value regarding the sensibility correction. This visual sensitivity correction is also the curve as shown in Fig. 3. For this index, for example, even a polarizing plate having a spectrum of orthogonal transmittance (Tp(λ)) shown in FIG. 4 (having a more uniform orthogonal transmittance among the entire wavelengths of B, G, and R) Or have the first The polarizing plate of the orthogonal transmittance (Tp(λ)) spectrum (the transmittance at the wavelength of G and R is low and the transmittance at the wavelength of B is high) is also symmetrical about 550 nm. The ground causes the sensitivity to decrease, and when the visual sensitivity correction is performed, both cases become the same value.

然而，考慮到上述所述之背光或彩色濾光片之特性時，由於紅色之波長區域對於亮度之貢獻較大，故可說是以如第5圖之類型之偏光板為較佳。 However, in consideration of the characteristics of the backlight or the color filter described above, since the wavelength region of red contributes a lot to the luminance, it can be said that a polarizing plate of the type shown in Fig. 5 is preferable.

若欲提升視感度校正偏光度，由於必須在全波長區域中整體性地提升偏光度，故在已接近理論上之極限值的現況下，雖然非常困難，但以從第4圖之類型改良成第5圖之類型的方向性來切換視點時，於其中即產生可改良之餘地，此可成為重大之突破。 If the degree of variability correction is to be improved, since the degree of polarization must be raised in the whole wavelength region as a whole, it is very difficult, but it is improved from the type of Fig. 4, although it is very close to the theoretical limit value. When the directionality of the type of Fig. 5 is used to switch the viewpoint, there is room for improvement in this, which can be a major breakthrough.

第6及7圖係分別表示對於具有第4及5圖所示之正交透射率Tc(λ)之光譜的偏光薄膜以上述式(1)定義之偏光薄膜單體對比(SCR(λ))的圖。比起正交透射率或偏光度等指標，由於偏光薄膜單體對比(SCR(λ))係相對於重疊2片偏光板之狀態之自然光之透射率之最小值的最大值的比率，故可認為是更接近實際液晶顯示裝置之對比之優劣的指標。 Figures 6 and 7 show the polarizing film monomer contrast (S CR (λ) as defined by the above formula (1) for the polarizing film having the spectrum of the orthogonal transmittance Tc(λ) shown in Figs. 4 and 5, respectively. ) of the map. The contrast ratio (S CR (λ)) of the polarizing film is a ratio of the maximum value of the minimum value of the transmittance of the natural light of the state in which the two polarizing plates are superimposed, as compared with the index of the orthogonal transmittance or the degree of polarization. It can be considered as an indicator that is closer to the comparison of actual liquid crystal display devices.

(偏光薄膜單體對比之測定方法) (Measurement method for comparison of polarizing film monomers)

以下，記載偏光薄膜單體對比(SCR(λ))之測定方法。 Hereinafter, a method of measuring the contrast of the polarizing film monomer (S CR (λ)) will be described.

<測定裝置> <Measurement device>

使用分光光度計作為Tp(λ)、Tc(λ)之測定裝置。為了更正確地評估Tc(λ)值，必須使用可測定到更高之吸光 度區域的分光光度計，在本發明中必須使用可進行吸光度7至8左右之測定的裝置。如此之分光光度計可列舉如日本分光(股)製之分光光度計(型號：V7100)等。 A spectrophotometer was used as a measuring device for Tp (λ) and Tc (λ). In order to evaluate the Tc(λ) value more correctly, it is necessary to use a measurable higher absorbance. In the spectrophotometer of the degree region, it is necessary to use a device capable of measuring the absorbance of about 7 to 8 in the present invention. Such a spectrophotometer may, for example, be a spectrophotometer (model: V7100) manufactured by JASCO Corporation.

就使直線偏振光(linear polarized light)射入之方法而言，一般已知者為使用由方解石等所構成之偏光稜鏡的方法，在本發明中之偏光稜鏡之消光比係設成10-5以下。 In the method of injecting a linear polarized light, a method of using a polarizing iridium composed of calcite or the like is generally known, and the extinction ratio of the polarizing yoke in the present invention is set to 10 -5 or less.

<測定試樣> <Measurement sample>

偏光板中，於偏光薄膜之單面或雙面多貼合有透明保護薄膜，但透明保護薄膜具有相位差特性，當以使其落後軸與偏光薄膜之吸收軸不呈平行亦不呈正交之方式貼合時，射入之直線偏振光會因透明保護薄膜之相位差特性而成為橢圓偏光，而無法正確地測定上述Tp(λ)、Tc(λ)。在評估如此之偏光板時，必須使透明保護薄膜解離偏光板而進行測定。當透明保護薄膜實質上不具有相位差特性時、或即使透明保護薄膜具有相位差特性但以使其落後軸與偏光薄膜之吸收軸呈平行或正交之方式貼合時，即使不使透明保護薄膜解離偏光板，亦可正確地測定上述Tp(λ)、Tc(λ)。 In the polarizing plate, a transparent protective film is attached to one side or both sides of the polarizing film, but the transparent protective film has a phase difference characteristic, and is not orthogonal or orthogonal to the absorption axis of the backward axis and the polarizing film. When the film is bonded in this manner, the linearly polarized light that is incident becomes elliptically polarized due to the phase difference characteristic of the transparent protective film, and the above-described Tp(λ) and Tc(λ) cannot be accurately measured. When evaluating such a polarizing plate, it is necessary to dissociate the transparent protective film from the polarizing plate for measurement. When the transparent protective film does not substantially have a phase difference characteristic, or even if the transparent protective film has a phase difference characteristic, such that the backward axis and the absorption axis of the polarizing film are parallel or orthogonal, even if the transparent protection is not provided When the film is dissociated from the polarizing plate, the above Tp(λ) and Tc(λ) can be accurately measured.

<測定> <Measurement>

使用上述分光光度計，對於偏光薄膜射入直線偏振光(波長λ nm)，以各波長分別測定依直線偏振光與平行尼科耳鏡之關係而測定之透射率(平行透射率：Tp(λ))、依直線偏振光與正交尼科耳鏡之關係而測定之透射率(正交透射率：Tc(λ))。更進一步，從測定之Tp(λ)、Tc(λ)依據上述式 (1)而求得SCR(λ)。 Using the above spectrophotometer, the polarized film is incident on linearly polarized light (wavelength λ nm), and the transmittance measured by the relationship between the linearly polarized light and the parallel Nicols is measured at each wavelength (parallel transmittance: Tp (λ) )), transmittance measured according to the relationship between linearly polarized light and crossed Nicols (orthogonal transmittance: Tc (λ)). Further, S CR (λ) is obtained from the measured Tp(λ) and Tc(λ) according to the above formula (1).

(偏光薄膜之特性) (Characteristics of polarizing film)

本發明之液晶顯示裝置所用之偏光板的特性係必須為上述式(1)所定義之各波長之偏光薄膜單體對比(SCR(λ))滿足下述式(2)之關係的偏光板。 The characteristics of the polarizing plate used in the liquid crystal display device of the present invention are those in which the polarizing film monomer ratio (S CR (λ)) of each wavelength defined by the above formula (1) satisfies the relationship of the following formula (2). .

[(SCR(550)+SCR(600))/2]≧30,000…(2) [(S CR (550)+S CR (600))/2]≧30,000...(2)

在此，上述式(2)之[(SCR(550)+SCR(600))/2]為30000以上，較佳為40000以上者，可使顯示裝置之對比變佳。相反地，當未達30000時，會有無法獲得顯示裝置之對比的不良情形。SCR(550)及SCR(600)係各自單獨地以30000以上為佳，以40000以上為更佳。 Here, [(S CR (550) + S CR (600))/2] of the above formula (2) is 30,000 or more, preferably 40,000 or more, and the contrast of the display device can be improved. Conversely, when it is less than 30,000, there is a problem that the comparison of the display devices cannot be obtained. Each of S CR (550) and S CR (600) is preferably 30,000 or more, more preferably 40,000 or more.

藉由從具有第6圖所示之SCR(λ)特性的偏光板變換成具有第7圖所示之SCR(λ)特性之類型的偏光板，雖使550nm或600nm之SCR變高，但450nm附近之SCR反而下降，而變成如下之關係：[(SCR(550)+SCR(600))/2]>SCR(450)此係由於例如在吸附定向有碘之偏光薄膜中，藉由後述之高溫高濕處理，使偏光薄膜中之碘中之I5之比例增加，而增加高波長側之吸收，相對地因I3之比例減少而導致低波長側之吸收減少之故。又，亦有因高溫高濕處理而使碘本身之定向度多少有所上昇之現象，亦確認到因此而導致整體性之SCR之上昇。 With the type of characteristics ([lambda]) transformed from the first polarizing plate S shown in FIG. 6 having the CR (λ) to have a characteristic shown in FIG. 7 CR S of the polarizing plate, and though the S 550nm or 600nm high CR However, the S CR near 450 nm decreases and becomes the following relationship: [(S CR (550) + S CR (600)) / 2] > S CR (450) This is due to, for example, iodine polarization in the adsorption orientation. In the film, the ratio of I 5 in the iodine in the polarizing film is increased by the high-temperature and high-humidity treatment described later, and the absorption on the high-wavelength side is increased, and the absorption on the low-wavelength side is relatively reduced due to the decrease in the ratio of I 3 . The reason. In addition, there has been a phenomenon in which the degree of orientation of iodine itself has increased due to high-temperature and high-humidity treatment, and it has also been confirmed that the overall SCR is increased.

如上所述，即使B(藍)區域之波長下之偏光薄膜單體對比降低，當使用於藍色之貢獻少之LED背光或彩色濾光 片時，若考慮到視感度校正則不太會造成問題，故R(紅)、G(綠)區域之波長下之偏光薄膜單體對比會優先，而使液晶顯示裝置之畫面之對比提升。 As described above, even if the contrast of the polarizing film monomer at the wavelength of the B (blue) region is lowered, when the LED backlight or the color filter is used with little contribution to the blue color In the case of film, if the visual sensitivity correction is considered, the problem is less likely to occur, so that the contrast of the polarizing film at the wavelengths of the R (red) and G (green) regions is prioritized, and the contrast of the screen of the liquid crystal display device is improved.

此係從與以往對於偏光板所要求之Ty或Py等之視點完全不同的視點來追求顯示裝置之對比特性者，現今，在偏光性能已為理論上之極限附近之偏光板的開發中，可說是對於顯示裝置之高對比化的一大突破。 This is to pursue the contrast characteristics of the display device from a viewpoint that is completely different from the viewpoint of Ty or Py required for the polarizing plate in the past. Nowadays, in the development of a polarizing plate in which the polarization performance is already near the theoretical limit, Said to be a breakthrough in the high contrast of display devices.

(偏光板之製作方法) (Method of manufacturing polarizing plate)

本發明之偏光板可例如依下述而製作，但不限於此。 The polarizing plate of the present invention can be produced, for example, as follows, but is not limited thereto.

(1)偏光薄膜製作步驟 (1) Polarizing film production steps

構成偏光薄膜之聚乙烯醇系樹脂通常係藉由將聚乙酸乙烯酯系樹脂予以皂化而獲得。聚乙烯醇系樹脂之皂化度通常為85莫耳%以上、較佳為90莫耳%以上、更佳為99至100莫耳%。就聚乙酸乙烯酯系樹脂而言，除了作為乙酸乙烯酯之均聚物的聚乙酸乙烯酯以外，亦可列舉如乙酸乙烯酯及可與其共聚合之其他單體的共聚物，例如乙烯-乙酸乙烯酯共聚物等。可與乙酸乙烯酯共聚合之其他單體列舉如不飽和羧酸類、烯烴類、乙烯醚類、不飽和磺酸類等。聚乙烯醇系樹脂之聚合度通常係在1000至10000之範圍內，較佳為在1500至5000之範圍內。 The polyvinyl alcohol-based resin constituting the polarizing film is usually obtained by saponifying a polyvinyl acetate-based resin. The degree of saponification of the polyvinyl alcohol-based resin is usually 85 mol% or more, preferably 90 mol% or more, more preferably 99 to 100 mol%. In the case of the polyvinyl acetate-based resin, in addition to the polyvinyl acetate which is a homopolymer of vinyl acetate, a copolymer such as vinyl acetate and other monomers copolymerizable therewith, such as ethylene-acetic acid, may also be mentioned. Vinyl ester copolymer and the like. Other monomers copolymerizable with vinyl acetate include, for example, unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and the like. The degree of polymerization of the polyvinyl alcohol-based resin is usually in the range of from 1,000 to 10,000, preferably from 1,500 to 5,000.

此等聚乙烯醇系樹脂可經改質，例如亦可使用經醛類改質之聚乙烯基甲縮醛(polyvinylformal)、聚乙烯基乙縮醛(polyvinylacetal)、聚乙烯基丁縮醛(polyvinylbutyral)等。通常，製造偏光薄膜時之起始材 料係使用厚度為20至100μm、較佳為30至80μm之聚乙烯醇系樹脂薄膜之未延伸薄膜。在工業上，薄膜之寬度以1500至4000mm為實用。將此未延伸薄膜依序以膨潤處理、染色處理、硼酸處理、水洗處理之順序進行處理，並在至硼酸處理為止之步驟施行單軸延伸，最後乾燥而獲得之偏光薄膜之厚度為例如5至50μm。 These polyvinyl alcohol-based resins may be modified, for example, aldehyde-modified polyvinylformal, polyvinylacetal, polyvinyl butyral (polyvinylbutyral) may also be used. )Wait. Usually, the starting material for producing a polarizing film The material is an unstretched film of a polyvinyl alcohol-based resin film having a thickness of 20 to 100 μm, preferably 30 to 80 μm. Industrially, the width of the film is practical from 1500 to 4000 mm. The unstretched film is sequentially treated in the order of swelling treatment, dyeing treatment, boric acid treatment, and water washing treatment, and uniaxially stretching is performed at a step up to the treatment with boric acid, and the thickness of the polarizing film obtained by the final drying is, for example, 5 to 50 μm.

偏光薄膜之製作方法大致分為2種製造方法。第1種方法係將聚乙烯醇系樹脂薄膜在空氣或惰性氣體中進行單軸延伸後，依序以膨潤處理步驟、染色處理步驟、硼酸處理步驟及水洗處理步驟之順序進行溶液處理，最後進行乾燥之方法。第2種方法係將未延伸之聚乙烯醇系樹脂薄膜於水溶液依序以膨潤處理步驟、染色處理步驟、硼酸處理步驟及水洗處理步驟之順序進行溶液處理，並在硼酸處理步驟及/或之前的步驟中以濕式進行單軸延伸，最後進行乾燥之方法。 The manufacturing method of the polarizing film is roughly classified into two manufacturing methods. In the first method, the polyvinyl alcohol-based resin film is uniaxially stretched in air or an inert gas, and then subjected to solution treatment in the order of a swelling treatment step, a dyeing treatment step, a boric acid treatment step, and a water washing treatment step, and finally, The method of drying. In the second method, the unstretched polyvinyl alcohol-based resin film is subjected to solution treatment in the order of the swelling treatment step, the dyeing treatment step, the boric acid treatment step, and the water washing treatment step in the aqueous solution, and before and/or before the boric acid treatment step. In the step of uniaxial stretching in a wet manner, the method of drying is finally carried out.

無論在任一方法中，單軸延伸皆可在1個步驟中進行，亦可在2個以上之步驟中進行。延伸方法可採用公知之方法，例如有：在搬送薄膜之壓送輥(nip roller)間賦予周速差而進行延伸之輥間延伸法、如日本專利第2731813號記載之熱輥延伸法、拉幅機(tenter)延伸法等。此外，基本上步驟之順序係如上所述，但處理浴之數目或處理條件等並無限制。又，亦可依其他之目的而附加上述第1種方法及第2種方法未記載之步驟。該步驟之例可列舉如：在硼酸處理後，以不含硼酸之碘化物水溶液進行浸漬處理 (碘化物處理)、或以不含硼酸之含有氯化鋅等之水溶液進行浸漬處理(鋅處理)等。 In either method, the uniaxial stretching can be carried out in one step or in two or more steps. The stretching method may be a known method, for example, an inter-roll stretching method in which a peripheral speed difference is imparted between a nip roller for conveying a film, and a hot roll stretching method as described in Japanese Patent No. 2731813, A tenter extension method, etc. Further, the order of the basic steps is as described above, but the number of processing baths, processing conditions, and the like are not limited. Further, steps not described in the first method and the second method may be added for other purposes. Examples of the step include, for example, immersion treatment with an aqueous solution of boric acid-free iodide after boric acid treatment. (Iodide treatment), or immersion treatment (zinc treatment) or the like in an aqueous solution containing no zinc borate or the like.

膨潤處理步驟係以去除薄膜表面之異物、去除薄膜中之可塑劑、賦予下個步驟之易染色性、達成薄膜之可塑化等目的而進行。處理條件係在可達成此等目的之範圍中、且不會發生基材薄膜之極端溶解或反透明化等不良情況的範圍中決定。使已預先在氣體中經延伸之薄膜膨潤時，係例如將薄膜浸漬在20至70℃、較佳為30至60℃之水溶液中而進行。薄膜之浸漬時間為30至300秒，較佳為60至240秒。使自始就未經延伸之原片薄膜膨潤時，係將薄膜浸漬在例如10至50℃、較佳為20至40℃之水溶液中而進行。薄膜之浸漬時間為30至300秒，更佳為60至240秒。 The swelling treatment step is carried out for the purpose of removing foreign matter on the surface of the film, removing the plasticizer in the film, imparting dyeability to the next step, and achieving plasticization of the film. The treatment conditions are determined within a range in which such a purpose can be achieved without causing problems such as extreme dissolution or reverse transparency of the base film. When the film which has been previously stretched in the gas is swollen, for example, the film is immersed in an aqueous solution of 20 to 70 ° C, preferably 30 to 60 ° C. The immersion time of the film is from 30 to 300 seconds, preferably from 60 to 240 seconds. When the original film which has not been stretched from the beginning is swollen, the film is immersed in an aqueous solution of, for example, 10 to 50 ° C, preferably 20 to 40 ° C. The immersion time of the film is from 30 to 300 seconds, more preferably from 60 to 240 seconds.

在膨潤處理步驟中，由於薄膜會在寬度方向膨潤而容易產生在薄膜有皺紋等之問題，故以使用擴寬輥(撐脹輥(expander roll))、螺滾式揉輥(spiral roll)、凸面輥(crown roll)、導布裝置(cloth guider)、彎曲棒(bend bar)、拉幅機夾具(tenter clip)等公知之擴寬裝置將薄膜之皺紋取去同時搬送薄膜為佳。在使浴中之薄膜搬送安定化之目的下，以水中淋浴調控膨潤浴中之水流、或併用EPC(Edge Position Control邊緣定位控制裝置：一種用以檢測薄膜之端部且防止薄膜之蛇行的裝置)等亦為有用。在本步驟中，由於薄膜在薄膜之搬送方向亦會膨潤擴大，故為了消除搬送方向之薄膜鬆弛，以施行例如控制處理槽前後之搬送輥之速度等手段為佳。此外，使用之膨潤處理浴除 了可使用純水以外，亦可使用在0.01至0.1重量%之範圍添加有硼酸(記載於日本特開平10-153709號公報)、氯化物(記載於日本特開平06-281816號公報)、無機酸、無機鹽、水溶性有機溶媒、醇類等的水溶液。 In the swelling treatment step, since the film swells in the width direction and is liable to cause wrinkles or the like in the film, a widening roll (expander roll), a spiral roll, or a spiral roll are used. A known widening device such as a crown roll, a cloth guide, a bend bar, or a tenter clip preferably removes the wrinkles of the film while conveying the film. In order to stabilize the film in the bath, the water in the swelling bath is controlled by a shower in the water, or EPC (Edge Position Control) is used. A device for detecting the end of the film and preventing the film from being snaked. ) is also useful. In this step, since the film is swollen and expanded in the direction in which the film is conveyed, it is preferable to perform, for example, a method of controlling the speed of the transfer roller before and after the treatment tank in order to eliminate the film slack in the conveyance direction. In addition, the swelling treatment bath used In addition to the use of pure water, boric acid (described in JP-A-10-153709), chloride (described in JP-A-H06-281816), and inorganics may be added in an amount of 0.01 to 0.1% by weight. An aqueous solution of an acid, an inorganic salt, a water-soluble organic solvent, or an alcohol.

以二色性色素進行之染色處理步驟，係以使二色性色素吸附、定向於薄膜等為目的而進行。處理條件係在可達成此等目的之範圍內、且在不會發生基材薄膜之極端溶解或反透明化等不良情形之範圍內決定。當使用碘作為二色性色素時，例如在10至45℃、較佳為20至35℃之溫度條件下，使用重量比為碘/碘化鉀/水=0.003至0.2/0.1至10/100之濃度之水溶液，以30至600秒、較佳為60至300秒進行浸漬處理。亦可使用其他碘化物、例如碘化鋅等來替代碘化鉀。此外，亦可將其他碘化物與碘化鉀併用。再者，亦可同時共存有碘化物以外之化合物，例如硼酸、氯化鋅、氯化鈷等。添加硼酸時，係以含有碘之特點而與下述硼酸處理有所區別。只要是相對於水100重量份，含有碘0.003重量份以上者，即可視為染色槽。 The dyeing treatment step with the dichroic dye is carried out for the purpose of adsorbing and orienting the dichroic dye to the film. The treatment conditions are determined within a range in which such a purpose can be achieved, and in the case where an abnormality such as extreme dissolution or reverse transparency of the base film does not occur. When iodine is used as the dichroic dye, for example, at a temperature of 10 to 45 ° C, preferably 20 to 35 ° C, a weight ratio of iodine/potassium iodide/water=0.003 to 0.2/0.1 to 10/100 is used. The aqueous solution is subjected to an immersion treatment in an amount of 30 to 600 seconds, preferably 60 to 300 seconds. Other iodides, such as zinc iodide, may be used in place of potassium iodide. In addition, other iodides may be used in combination with potassium iodide. Further, a compound other than the iodide such as boric acid, zinc chloride, cobalt chloride or the like may be coexisted at the same time. When boric acid is added, it is distinguished from the following boric acid treatment by the characteristic of containing iodine. As long as it contains 0.003 part by weight or more of iodine with respect to 100 parts by weight of water, it can be regarded as a dyeing tank.

當使用水溶性二色性染料作為二色性色素時，例如在20至80℃、較佳為30至70℃之溫度條件下，使用重量比為二色性染料/水=0.001至0.1/100之濃度之水溶液，以30至600秒、較佳為60至300秒進行浸漬處理。所使用之二色性染料之水溶液亦可含有染色助劑等，例如亦可含有硫酸鈉等無機鹽、界面活性劑等。二色性染料可單獨使用，亦可併用2種以上之二色性染料。 When a water-soluble dichroic dye is used as the dichroic dye, for example, at a temperature of 20 to 80 ° C, preferably 30 to 70 ° C, the weight ratio is dichroic dye/water = 0.001 to 0.1/100. The aqueous solution of the concentration is subjected to an immersion treatment for 30 to 600 seconds, preferably 60 to 300 seconds. The aqueous solution of the dichroic dye to be used may further contain a dyeing assistant or the like, and may contain, for example, an inorganic salt such as sodium sulfate or a surfactant. The dichroic dye may be used singly or in combination of two or more kinds of dichroic dyes.

如上所述，亦可於染色槽中延伸薄膜。延伸係藉由使染色槽之前後之軋輥具有周速差等之方法而進行。此外，與膨潤處理步驟同樣地，亦可在染色浴中及/或浴出入口設置擴寬輥(撐脹輥)、螺滾式揉輥、凸面輥、導布裝置、彎曲棒等。 As described above, the film can also be stretched in the dyeing tank. The stretching is performed by a method in which the rolls before and after the dyeing tank have a peripheral speed difference or the like. Further, similarly to the swelling treatment step, a widening roller (elevating roller), a spiral roller, a convex roller, a guide cloth, a bending bar, or the like may be provided in the dye bath and/or the bath inlet and outlet.

硼酸處理係藉由將經二色性色素染色之聚乙烯醇系樹脂薄膜浸漬在相對於水100重量份含有硼酸1至10重量份之水溶液中而進行。當二色性色素為碘時，以含有碘化物1至30重量份為佳。碘化物可列舉如碘化鉀、碘化鋅等。又，亦可同時共存有碘化物以外之化合物，例如氯化鋅、氯化鈷、氯化鋯、硫代硫酸鈉、亞硫酸鉀、硫酸鈉等。 The boric acid treatment is carried out by immersing the polyvinyl alcohol-based resin film dyed with the dichroic dye in an aqueous solution containing 1 to 10 parts by weight of boric acid per 100 parts by weight of water. When the dichroic dye is iodine, it is preferably 1 to 30 parts by weight based on the iodide. Examples of the iodide include potassium iodide, zinc iodide, and the like. Further, a compound other than the iodide such as zinc chloride, cobalt chloride, zirconium chloride, sodium thiosulfate, potassium sulfite, sodium sulfate or the like may be coexisted at the same time.

硼酸處理係為了要利用交聯而達成耐水化或色相調整(防止帶有藍色感等)等而實施。當為了要利用交聯而達成耐水化而進行硼酸處理時，亦可因應需要而在硼酸以外、或與硼酸一起，使用乙二醛(glyoxal)、戊二醛(glutaraldehyde)等交聯劑。又，有時亦將用以達成耐水化之硼酸處理稱為耐水化處理、交聯處理、固定化處理等名稱。此外，有時亦將用以色相調整之硼酸處理稱為補色處理、再染色處理等名稱。 The boric acid treatment is carried out in order to achieve water resistance, hue adjustment (preventing a blue sensation, etc.) by cross-linking. When the boric acid treatment is carried out in order to achieve hydration resistance by crosslinking, a crosslinking agent such as glyoxal or glutaraldehyde may be used in addition to or in addition to boric acid. Further, the boric acid treatment for achieving water resistance is sometimes referred to as a water resistance treatment, a crosslinking treatment, and an immobilization treatment. In addition, the boric acid treatment for adjusting the hue is sometimes referred to as a complementary color treatment or a re-dye treatment.

此硼酸處理係依據其目的而適當變更硼酸及碘化物之濃度、處理浴之溫度以進行。用以達成耐水化之硼酸處理、用以達成色相調整之硼酸處理雖然並無特別區分，但可依下述條件實施。當將原片薄膜進行膨潤處理、染色處理、硼酸處理，且硼酸處理係以利用交聯達成耐水化為目的 時，使用相對於水100重量份含有硼酸3至10重量份、碘化物1至20重量份之硼酸處理浴，通常在50至70℃、較佳為在55至65℃之溫度下進行。浸漬時間為90至300秒。又，當對於已預先經延伸之薄膜進行染色處理、硼酸處理時，硼酸處理浴之溫度通常為50至85℃、較佳為55至80℃。 This boric acid treatment is carried out by appropriately changing the concentration of boric acid and iodide and the temperature of the treatment bath depending on the purpose. The boric acid treatment for achieving the hydration resistance and the boric acid treatment for achieving the hue adjustment are not particularly distinguished, but can be carried out under the following conditions. When the original film is subjected to swelling treatment, dyeing treatment, boric acid treatment, and boric acid treatment is to achieve water resistance by crosslinking. In the case of using a boric acid treatment bath containing 3 to 10 parts by weight of boric acid and 1 to 20 parts by weight of iodide with respect to 100 parts by weight of water, it is usually carried out at a temperature of 50 to 70 ° C, preferably 55 to 65 ° C. The immersion time is 90 to 300 seconds. Further, when the film which has been previously stretched is subjected to dyeing treatment or boric acid treatment, the temperature of the boric acid treatment bath is usually 50 to 85 ° C, preferably 55 to 80 ° C.

在用以達成耐水化之硼酸處理後，亦可進行用以達成色相調整之硼酸處理。例如，當二色性染料為碘時，為了達成此目的，係使用相對於水100重量份含有硼酸1至5重量份、碘化物3至30重量份之硼酸處理浴，通常在10至45℃之溫度下進行。浸漬時間通常為3至300秒、較佳為10至240秒。後續之用以達成色相調整之硼酸處理，相較於用以達成耐水化之硼酸處理，通常是以較低之硼酸濃度、較高之碘化物濃度、較低之溫度進行。 After the boric acid treatment for achieving water resistance, a boric acid treatment for achieving hue adjustment can also be performed. For example, when the dichroic dye is iodine, in order to achieve this, a boric acid treatment bath containing 1 to 5 parts by weight of boric acid and 3 to 30 parts by weight of iodide relative to 100 parts by weight of water is used, usually at 10 to 45 ° C. The temperature is carried out. The immersion time is usually from 3 to 300 seconds, preferably from 10 to 240 seconds. Subsequent boric acid treatment to achieve hue adjustment is generally carried out at a lower boric acid concentration, a higher iodide concentration, and a lower temperature than the boric acid treatment used to achieve hydration resistance.

此等硼酸處理可由複數個步驟所構成，通常多半是由2至5個步驟進行。此時，使用之各硼酸處理槽之水溶液組成、溫度係在上述範圍內，可為相同或不同。上述用以達成耐水化之硼酸處理、用以達成色相調整之硼酸處理亦可各自以複數個步驟進行。 These boric acid treatments may consist of a plurality of steps, usually carried out in two to five steps. In this case, the aqueous solution composition and the temperature of each of the boric acid treatment tanks used are in the above range, and may be the same or different. The boric acid treatment for achieving the hydration resistance and the boric acid treatment for achieving the hue adjustment may be carried out in a plurality of steps.

又，即使在硼酸處理步驟中，亦可與染色處理步驟同樣地進行薄膜之延伸。最終之累積延伸倍率為4至7倍，較佳為4.5至6.5倍。在此，所謂「累積延伸倍率」係意指原片薄膜之長度方向基準長度在完成所有延伸處理後之薄膜中成為何等程度之長度，例如原片薄膜中原本為1m之 部分在完成所有延伸處理後之薄膜中若成為5m，則此時之累積延伸倍率為5倍。 Further, even in the boric acid treatment step, the film can be stretched in the same manner as the dyeing treatment step. The final cumulative stretching ratio is 4 to 7 times, preferably 4.5 to 6.5 times. Here, the term "accumulated stretch ratio" means the length of the length direction reference length of the original film on the film after completion of all the stretching processes, for example, the original film is originally 1 m. When the film was partially 5 m in the film after completion of all the stretching treatment, the cumulative stretching ratio at this time was 5 times.

在硼酸處理後，進行水洗處理。水洗處理係藉由將為了獲致耐水化及/或色相調整而經硼酸處理之聚乙烯醇系樹脂薄膜浸漬於水中、或以水進行噴霧淋浴、或併用浸漬與噴霧而進行。水洗處理中之水之溫度通常為2至40℃，浸漬時間為2至120秒。 After the boric acid treatment, a water washing treatment is performed. The water-washing treatment is carried out by immersing the boric acid-treated polyvinyl alcohol-based resin film in water for the purpose of obtaining water resistance and/or hue adjustment, or by spraying with water or by immersion and spraying. The temperature of the water in the water washing treatment is usually 2 to 40 ° C, and the immersion time is 2 to 120 seconds.

在此，在延伸處理後之各個步驟中，亦可以使薄膜之張力分別實質上成為定值之方式進行張力調控。具體而言，在染色處理步驟中完成延伸時，係在其後之硼酸處理步驟及水洗處理步驟中進行張力調控。在染色處理步驟之前步驟中完成延伸時，則在包含染色處理步驟及硼酸處理步驟之其後之步驟中進行張力調控。當硼酸處理步驟係由複數個硼酸處理步驟所構成時，較佳係在最初或從最初至第2階段為止之硼酸處理步驟中延伸前述薄膜，並在已進行延伸處理之硼酸處理步驟之下一個硼酸處理步驟至水洗步驟為止之各個步驟中進行張力調控；或是在從最初至第3階段之硼酸處理步驟中延伸前述薄膜，並在已進行延伸處理之硼酸處理步驟之下一個硼酸處理步驟至水洗步驟為止之各個步驟中進行張力調控。就工業上而言，更佳係在最初或從最初至第2階段為止之硼酸處理步驟中延伸前述薄膜，並在已進行延伸處理之硼酸處理步驟之下一個硼酸處理步驟至水洗步驟為止之各個步驟中進行張力調控。又，在硼酸處理後，當進行上述碘化物處理或鋅處理時， 亦可對此等步驟進行張力調控。 Here, in each step after the stretching treatment, the tension of the film may be substantially controlled so that the tension of the film is substantially constant. Specifically, when the stretching is completed in the dyeing treatment step, the tension regulation is performed in the subsequent boric acid treatment step and the water washing treatment step. When the stretching is completed in the step before the dyeing treatment step, the tension control is performed in the step including the dyeing treatment step and the boric acid treatment step. When the boric acid treatment step is constituted by a plurality of boric acid treatment steps, it is preferred to extend the film in the boric acid treatment step initially or from the first to the second stage, and under the boric acid treatment step which has been subjected to the elongation treatment Performing tension control in each step from the boric acid treatment step to the water washing step; or extending the film in the boric acid treatment step from the first to the third stage, and performing a boric acid treatment step under the boric acid treatment step which has been subjected to the extension treatment to Tension control is performed in each step up to the water washing step. Industrially, it is preferred to extend the film in the boric acid treatment step initially or from the first to the second stage, and each of the boric acid treatment step to the water washing step under the boric acid treatment step in which the elongation treatment has been carried out Tension control is carried out in the step. Further, after the boric acid treatment, when the above iodide treatment or zinc treatment is performed, Tension adjustment can also be performed for these steps.

就用以調控張力之軋輥、用以控制薄膜之搬送方向的導輥(guide roll)而言，可使用橡膠輥、不銹鋼製研磨輥、海綿橡膠輥等。就橡膠輥而言，以由NBR等所構成且其硬度為依JIS K 6301之試驗方法所測定之JIS蕭氏C刻度(JIS Shore C scale)為60至90度(更佳為70至80度)者為較佳。就不銹鋼製研磨輥而言，以由SUS304、SUS316等所構成，且在達成膜厚一致化之目的下，其表面粗糙度以JIS B 0601(表面粗糙度)之粗糙度曲線之局部山頂之平均間隔S表示為約0.2至1.0S者為較佳。就海綿橡膠輥而言，以海綿之硬度為依JIS K 6301之試驗方法所測定之JIS蕭氏C刻度為20至60度(更佳為25至50度)、密度為0.4至0.6g/m3(更佳為0.42至0.57g/cm3)者為較佳。 For the roller for regulating the tension and the guide roller for controlling the conveying direction of the film, a rubber roller, a stainless steel grinding roller, a sponge rubber roller or the like can be used. In the case of the rubber roller, the JIS Shore C scale measured by a test method of NBR or the like and having a hardness of JIS K 6301 is 60 to 90 degrees (more preferably 70 to 80 degrees). ) is better. The stainless steel polishing roll is made of SUS304, SUS316, etc., and the surface roughness is the average of the partial peaks of the roughness curve of JIS B 0601 (surface roughness) for the purpose of achieving uniform film thickness. It is preferred that the interval S is expressed as about 0.2 to 1.0 s. In the case of a sponge rubber roller, the JIS Xiao C scale measured by the test method of JIS K 6301 is 20 to 60 degrees (more preferably 25 to 50 degrees) and the density is 0.4 to 0.6 g/m. 3 (more preferably 0.42 to 0.57 g/cm 3 ) is preferred.

在從膨潤處理至水洗處理為止之各個步驟中的張力係可為相同或不同，在張力調控中對於薄膜之張力並無特別限定，以每單位寬度計，係適宜設定為150至2000N/m、較佳為600至1500N/m之範圍內。當張力低於150N/m時，薄膜容易產生皺紋。另一方面，當張力超過2000N/m時，會發生薄膜破裂或軸承(bearing)磨耗所導致之低壽命化等問題。此外，此每單位寬度之張力係由該步驟之入口附近之薄膜寬度與張力檢測器之張力值而計算出。又，當進行張力調控時，雖然不可避免地會有些許延伸/收縮之情形，但在本發明中，此等不包含於延伸處理中。 The tension in each step from the swelling treatment to the water washing treatment may be the same or different, and the tension of the film in the tension control is not particularly limited, and is suitably set to 150 to 2000 N/m per unit width. It is preferably in the range of 600 to 1500 N/m. When the tension is less than 150 N/m, the film is prone to wrinkles. On the other hand, when the tension exceeds 2000 N/m, problems such as film breakage or bearing wear due to low wear life may occur. Further, the tension per unit width is calculated from the film width near the entrance of the step and the tension value of the tension detector. Further, when tension regulation is performed, although there is inevitably a slight extension/contraction, in the present invention, these are not included in the elongation treatment.

在偏光薄膜製作步驟之最後，進行乾燥處理。乾燥處 理雖然以逐漸改變張力並以多數階段進行為佳，但從設備上之限制等來看，通常以2至3階段進行。當以2階段進行時，前段之張力較佳係設定為600至1500N/m之範圍，後段之張力較佳係設定為250至1200N/m之範圍。若張力太大，則薄膜之破裂會變多，若太小，則產生之皺紋會變多，而較不佳。此外，前段之乾燥溫度較佳係設定為30至90℃之範圍，後段之乾燥溫度較佳係設定為40至100℃之範圍。若溫度太高，則薄膜之破裂會變多且光學特性降低，若溫度太低，則條紋會變多，而較不佳。乾燥處理溫度可設為例如60至600秒，各階段之乾燥時間可相同或不同。時間若太長，則在生產性方面不佳，時間若太短，則乾燥會不充分而不佳。 At the end of the polarizing film production step, a drying treatment is performed. Dry place Although it is preferable to gradually change the tension and perform it in most stages, it is usually carried out in two to three stages from the viewpoint of equipment limitations and the like. When the two stages are carried out, the tension of the front stage is preferably set to a range of 600 to 1500 N/m, and the tension of the latter stage is preferably set to a range of 250 to 1200 N/m. If the tension is too large, the rupture of the film will increase. If it is too small, wrinkles will become more and less. Further, the drying temperature of the preceding stage is preferably set to a range of from 30 to 90 ° C, and the drying temperature of the latter stage is preferably set to a range of from 40 to 100 ° C. If the temperature is too high, the rupture of the film will increase and the optical characteristics will decrease. If the temperature is too low, the streaks will become more and less. The drying treatment temperature may be set to, for example, 60 to 600 seconds, and the drying times of the respective stages may be the same or different. If the time is too long, it will be poor in terms of productivity. If the time is too short, the drying will be insufficient.

如此，對於聚乙烯醇系樹脂薄膜施行單軸延伸、二色性色素之染色處理及硼酸處理而獲得偏光薄膜。此偏光薄膜之厚度通常在5至40μm之範圍內。 In this manner, the polyvinyl alcohol-based resin film was subjected to uniaxial stretching, dyeing treatment of dichroic dye, and boric acid treatment to obtain a polarizing film. The thickness of this polarizing film is usually in the range of 5 to 40 μm.

(2)對於偏光薄膜賦予滿足式(2)、(3)之特性的方法 (2) A method of imparting characteristics satisfying the formulas (2) and (3) to a polarizing film

本發明之偏光板中所使用之偏光薄膜係具有下述式(2)所示之特性。具有本特性之偏光薄膜係藉由使偏光薄膜保持於特定環境下而獲得。亦即，必須使偏光薄膜保持於至少流動方向(吸收軸方向)之收縮受到抑制的狀態、且保持於高溫高濕度之環境下。 The polarizing film used in the polarizing plate of the present invention has the characteristics shown by the following formula (2). A polarizing film having this characteristic is obtained by keeping a polarizing film in a specific environment. In other words, it is necessary to maintain the polarizing film in a state where the shrinkage in at least the flow direction (absorption axis direction) is suppressed, and it is maintained in an environment of high temperature and high humidity.

[(SCR(550)+SCR(600))/2]≧30,000…(2) [(S CR(550) +S CR(600) )/2]≧30,000...(2)

在偏光薄膜之收縮未受抑制的狀態下，經單軸延伸而製作之偏光薄膜會大幅收縮而失去偏光性能。關於抑制偏 光薄膜之收縮的狀態，可列舉如在對偏光薄膜維持張力之狀態下保持於高溫高濕槽中的方法、將薄膜積層於水分率高之偏光薄膜之雙面並在偏光薄膜之水分高之狀態下賦予高溫的方法等。前者中之張力為15×104N/m2至1500×104N/m2、更佳為150×104N/m2至1200×104N/m2。若低於15×104N/m2，則容易失去偏光性能，若為1500×104N/m2以上則會變得容易破裂。 In the state where the shrinkage of the polarizing film is not suppressed, the polarizing film produced by the uniaxial stretching shrinks greatly and loses the polarizing performance. The state in which the shrinkage of the polarizing film is suppressed is a method of maintaining the film in a high-temperature and high-humidity bath while maintaining the tension of the polarizing film, and laminating the film on both sides of the polarizing film having a high moisture content and moisture in the polarizing film. A method of imparting high temperature in a high state. The tension in the former is from 15 × 10 4 N/m 2 to 1500 × 10 4 N/m 2 , more preferably from 150 × 10 4 N/m 2 to 1200 × 10 4 N/m 2 . If it is less than 15 × 10 4 N/m 2 , the polarizing performance is liable to be lost, and if it is 1500 × 10 4 N/m 2 or more, the film is easily broken.

在後者之情形中，係藉由將後述透明保護薄膜等薄膜積層於偏光薄膜之雙面，而抑制偏光薄膜之收縮。此外，由於此方法係僅藉由將積層之偏光板加熱即可使偏光薄膜置於高溫高濕下，故當將偏光薄膜保持於高溫高濕環境下時，不須設置高溫高濕槽，此法簡便而較佳。 In the latter case, shrinkage of the polarizing film is suppressed by laminating a film such as a transparent protective film described later on both sides of the polarizing film. In addition, since the polarizing film is placed under high temperature and high humidity only by heating the laminated polarizing plate, when the polarizing film is maintained in a high temperature and high humidity environment, it is not necessary to provide a high temperature and high humidity groove. The method is simple and better.

所謂高溫高濕環境下係指溫度為40℃至90℃且濕度為50%至95%RH，較佳之範圍係指溫度為60℃至80℃且濕度為60%至90%RH之環境。當溫度未達40℃時、或濕度未達50%RH時，由於溫濕度不充分，故難以獲得式(3)記載之特性。當溫度為90℃以上時，偏光薄膜會明顯劣化並容易發生脫藍色，當濕度為95%RH以上時則會容易結露。 The so-called high temperature and high humidity environment means a temperature of 40 ° C to 90 ° C and a humidity of 50% to 95% RH, and a preferred range refers to an environment having a temperature of 60 ° C to 80 ° C and a humidity of 60% to 90% RH. When the temperature is less than 40 ° C or the humidity is less than 50% RH, the temperature and humidity are insufficient, so that it is difficult to obtain the characteristics described in the formula (3). When the temperature is 90 ° C or more, the polarizing film is significantly deteriorated and blue is likely to occur, and when the humidity is 95% RH or more, dew condensation is likely to occur.

曝露在高溫高濕環境下之時間為10秒至1200秒，較佳為20秒至600秒。時間若短則無法獲得充足之處理效果，若太長則偏光薄膜會明顯劣化並容易發生脫藍色，而較不佳。 The time of exposure to a high temperature and high humidity environment is from 10 seconds to 1200 seconds, preferably from 20 seconds to 600 seconds. If the time is short, sufficient processing effect cannot be obtained. If it is too long, the polarizing film will be significantly deteriorated and it is prone to de-bluening, which is less preferable.

在將薄膜積層於偏光薄膜之雙面並在偏光薄膜之水分 高之狀態下賦予高溫的方法中，由於難以將偏光薄膜所曝露之溫濕度環境予以數值化，故規定貼合後賦予高溫時之條件。該溫度為70℃以上，較佳為75℃以上，又，通常為100℃以下，較佳為90℃以下。溫度若太低則無法獲得充足之處理效果，若太高則偏光薄膜會明顯劣化並容易發生脫藍色，而較不佳。 Laying the film on both sides of the polarizing film and moisture in the polarizing film In the method of imparting high temperature in a high state, since it is difficult to quantify the temperature and humidity environment exposed by the polarizing film, the conditions at which high temperature is applied after bonding are specified. The temperature is 70 ° C or higher, preferably 75 ° C or higher, and usually 100 ° C or lower, preferably 90 ° C or lower. If the temperature is too low, sufficient treatment effect cannot be obtained. If it is too high, the polarizing film will be significantly deteriorated and it is prone to de-bluening, which is not preferable.

該處理係在從剛貼合後之40秒以內、較佳為在30秒以內、更佳為在20秒以內賦予高溫。到賦予高溫為止之時間若長，則偏光薄膜之水分會下降，而難以獲得處理效果。 This treatment is performed at a high temperature within 40 seconds, preferably within 30 seconds, and more preferably within 20 seconds from immediately after bonding. If the time until the high temperature is applied is long, the moisture of the polarizing film is lowered, and it is difficult to obtain a treatment effect.

貼合後賦予高溫之時間為10秒至1200秒、較佳為20秒至600秒。時間若短則無法獲得充足之處理效果，若太長則偏光薄膜會明顯劣化並容易發生脫藍色，而較不佳。 The time for applying the high temperature after lamination is from 10 seconds to 1200 seconds, preferably from 20 seconds to 600 seconds. Short time However, sufficient treatment effect cannot be obtained. If it is too long, the polarizing film will be significantly deteriorated and it is prone to de-bluening, which is less preferable.

水分率高之偏光薄膜係指水分率為9%以上、較佳為10%以上之偏光薄膜。若低於9%，則即使將薄膜積層於偏光薄膜之雙面並賦予高溫，亦難以獲得處理效果。若水分率太高，則在將薄膜積層於偏光薄膜之雙面時會產生皺紋等，而較不佳。水分率之上限通常為20%以下，更佳為15%以下。 The polarizing film having a high moisture content means a polarizing film having a water content of 9% or more, preferably 10% or more. If it is less than 9%, even if a film is laminated on both sides of the polarizing film and a high temperature is applied, it is difficult to obtain a treatment effect. If the moisture content is too high, wrinkles and the like may occur when the film is laminated on both sides of the polarizing film, which is less preferable. The upper limit of the moisture content is usually 20% or less, more preferably 15% or less.

偏光薄膜之水分率，係依據Fujiwork(股)製之紅外線水分率計IM-3SCV MODEL-1900(L)所測定之值並藉由下述式而求得者。 The moisture content of the polarizing film is determined by the following formula according to the value measured by the infrared moisture meter IM-3SCV MODEL-1900 (L) manufactured by Fujiwork Co., Ltd.

水分率=(1/28)＊(1.2145＊測定值-941.662) Moisture rate = (1/28) * (1.2145 * measured value - 941.662)

又，本式係由於水分率不同之偏光薄膜之水分率計數值、與於105℃熱處理1小時前後之水分量變化所得之水 分率之值幾乎為直線關係而獲得之關係式。 Further, this formula is a water content count value of a polarizing film having a different moisture content, and a water content obtained by changing a water content before and after heat treatment at 105 ° C for 1 hour. The value of the fraction is almost a linear relationship.

具有上述之較佳範圍內之水分率的偏光薄膜係可藉由調控例如偏光薄膜之乾燥溫度及乾燥時間而獲得，低水分率之偏光薄膜可藉由使乾燥爐之溫度設為較低、及/或乾燥時間設為較短而獲得，高水分率之偏光薄膜可藉由使乾燥爐之溫度設為較高、及/或乾燥時間設為較長而獲得。 The polarizing film having the moisture content in the above preferred range can be obtained by adjusting, for example, the drying temperature and the drying time of the polarizing film, and the polarizing film having a low moisture content can be set to lower the temperature of the drying furnace, and / or the drying time is set to be shorter, and the high moisture ratio polarizing film can be obtained by setting the temperature of the drying oven to be high, and/or the drying time to be long.

在本發明中，若欲獲得式(3)之性能，則在將薄膜積層於偏光薄膜之雙面並在偏光薄膜之水分高之狀態下賦予高溫的方法中，上述溫度、時間、水分率之組合甚為重要。 In the present invention, in order to obtain the performance of the formula (3), in the method of laminating the film on both sides of the polarizing film and imparting a high temperature in a state where the moisture of the polarizing film is high, the temperature, time, and moisture ratio are as described above. The combination is very important.

乾燥後，亦可更進一步在室溫或稍微高於室溫之溫度、例如20至50℃左右之溫度下以12至600小時左右進行熟化(curing)。熟化時之溫度一般係設定成低於乾燥時所採用之溫度。 After drying, it may be further cured at room temperature or a temperature slightly higher than room temperature, for example, at a temperature of about 20 to 50 ° C for about 12 to 600 hours. The temperature at the time of ripening is generally set to be lower than the temperature used for drying.

(3)透明保護薄膜等薄膜對於偏光薄膜之積層 (3) Thin film of transparent protective film for laminated film of polarizing film

將透明保護薄膜等薄膜積層於偏光薄膜之雙面的方法，係藉由接著劑層或直接積層薄膜。當將薄膜僅積層於偏光薄膜之單面時，由於其後即使賦予高溫，亦難以使偏光薄膜保持於高濕度環境下，故較不佳。 A method of laminating a film such as a transparent protective film on both sides of a polarizing film is performed by an adhesive layer or a direct laminated film. When the film is laminated only on one side of the polarizing film, it is difficult to maintain the polarizing film in a high-humidity environment even if it is given a high temperature thereafter, which is not preferable.

關於薄膜之積層，只要使用輥等將偏光薄膜與薄膜逐次於單面、或同時於雙面進行貼合即可。從製造效率之方面來看，以雙面同時貼合為佳。貼合溫度通常為15至30℃左右之範圍。當藉由接著劑層而積層時，可列舉如在偏光薄膜及/或透明保護薄膜之表面均勻地塗佈接著劑，並將另一方之薄膜疊合在塗佈面，藉由輥等而貼合，且予以 乾燥的方法等。通常接著劑係在其調製後於15至40℃之溫度下塗佈。 Regarding the laminate of the film, the polarizing film and the film may be bonded to each other on one side or simultaneously on both sides using a roll or the like. From the aspect of manufacturing efficiency, it is better to apply both sides at the same time. The bonding temperature is usually in the range of about 15 to 30 °C. When the layer is laminated by the adhesive layer, the adhesive is uniformly applied to the surface of the polarizing film and/or the transparent protective film, and the other film is laminated on the coated surface, and is attached by a roller or the like. And give Dry method, etc. Usually the adhesive is applied at a temperature of from 15 to 40 ° C after its preparation.

藉由接著劑時之接著劑可使用水溶媒系接著劑、有機溶媒系接著劑、熱熔系接著劑、無溶劑型接著劑等。水溶媒系接著劑可列舉如聚乙烯醇系樹脂水溶液、水系二液型胺酯(urethane)系乳液(emulsion)接著劑等，有機溶媒系接著劑可列舉如二液型胺酯系接著劑等，無溶劑型接著劑可列舉如一液型胺酯系接著劑、環氧系接著劑等。 A water-based adhesive, an organic solvent-based adhesive, a hot-melt adhesive, a solventless adhesive, or the like can be used as the adhesive for the adhesive. Examples of the aqueous solvent-based adhesive include a polyvinyl alcohol-based resin aqueous solution and an aqueous two-component urethane emulsion. Examples of the organic solvent-based adhesive include a two-component amine ester-based adhesive. Examples of the solvent-free adhesive include a one-part amine ester-based adhesive, an epoxy-based adhesive, and the like.

使用聚乙烯醇系樹脂水溶液時，在作為接著劑使用之聚乙烯醇系樹脂中，除了將作為乙酸乙烯酯之均聚物的聚乙酸乙烯酯予以皂化處理而獲得之乙烯醇均聚物以外，還有將乙酸乙烯酯與可與其共聚合之其他單體的共聚物予以皂化處理而獲得之乙烯醇系共聚物、更進一步將此等之羥基予以部分性地改質而成之改質聚乙烯醇系聚合物等。在此接著劑中亦可添加多元醛、水溶性環氧化合物、三聚氰胺系化合物、氧化鋯化合物、鋅化合物等作為添加劑。使用此等水系接著劑時，由其所得之接著劑層通常為1μm以下，即使使用通常之光學顯微鏡觀察剖面，事實上亦無法觀察到該接著劑層。 In the case of using a polyvinyl alcohol-based resin aqueous solution, a polyvinyl alcohol-based resin used as an adhesive is a vinyl alcohol homopolymer obtained by saponifying a polyvinyl acetate which is a homopolymer of vinyl acetate. Further, a vinyl alcohol-based copolymer obtained by saponifying a copolymer of vinyl acetate and another monomer copolymerizable therewith, and a modified polyethylene obtained by partially modifying the hydroxyl group An alcohol polymer or the like. A polyvalent aldehyde, a water-soluble epoxy compound, a melamine-based compound, a zirconia compound, a zinc compound or the like may be added as an additive to the adhesive. When such a water-based adhesive is used, the adhesive layer obtained therefrom is usually 1 μm or less, and the adhesive layer is not actually observed even when the cross section is observed by a usual optical microscope.

就接著劑而言，亦可使用光硬化型接著劑。就光硬化型接著劑而言，可列舉如在環氧樹脂、丙烯酸系樹脂、氧雜環丁烷(oxetane)樹脂、胺酯樹脂、聚乙烯醇樹脂等中添加自由基聚合型起始劑及/或陽離子聚合型起始劑而成者。其中，以在脂環式環氧樹脂與不具有脂環式結構之環 氧樹脂的混合物中添加陽離子聚合型起始劑而成者為佳。 As the adhesive, a photocurable adhesive can also be used. Examples of the photocurable adhesive include a radical polymerization type initiator and an epoxy resin, an acrylic resin, an oxetane resin, an amine ester resin, a polyvinyl alcohol resin, and the like. / or cationic polymerization type initiator. Among them, in the ring of alicyclic epoxy resin and without alicyclic structure It is preferred to add a cationic polymerization type initiator to the mixture of the oxygen resins.

當使用光硬化型接著劑而將偏光薄膜與貼合於其之薄膜予以接合時，在接合後，藉由照射活性能量線而使光硬化性接著劑硬化。活性能量線之光源並無特別限定，以在波長400nm以下具有發光分布之活性能量線為佳，具體而言，以低壓水銀燈、中壓水銀燈、高壓水銀燈、超高壓水銀燈、化學燈、黑光燈(black light lamp)、微波激發水銀燈、金屬鹵化物燈等為適用。對於光硬化型接著劑之光照射強度，係依據該光硬化性接著劑之組成而適宜決定，雖無特別限定，但以對於聚合起始劑之活性化為有效的波長區域之照射強度為0.1至6000mW/cm2為較佳。當該照射強度為0.1mW/cm2以上時，反應時間不會變太長，當為6000mW/cm2以下時，較不會發生因從光源發射之熱及光硬化型接著劑硬化時之發熱所導致的環氧樹脂之變黃或偏光薄膜之劣化。對於光硬化型接著劑之光照射時間係依要予以硬化之光硬化型接著劑所控制者，雖無特別限定，但較佳係設定成使上述照射強度與照射時間之乘積所表示的累積光量為10至10000mJ/cm2。當對於光硬化型接著劑之累積光量為10mJ/cm2以上時，可使源自聚合起始劑之活性種產生充足量而使硬化反應更確實地進行，當為10000mJ/cm2以下時，照射時間不會變太長，而可維持良好之生產性。又，照射活性能量線後之接著劑層之厚度通常為0.001至5μm左右，較佳為0.01μm以上，又，較佳為2μm以下、更佳為1μm以下。 When a polarizing film is bonded to a film bonded thereto by using a photocurable adhesive, the photocurable adhesive is cured by irradiation of an active energy ray after bonding. The light source of the active energy ray is not particularly limited, and is preferably an active energy ray having a light-emitting distribution at a wavelength of 400 nm or less. Specifically, a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high pressure mercury lamp, a chemical lamp, and a black light lamp ( Black light lamp), microwave-excited mercury lamp, metal halide lamp, etc. are suitable. The light irradiation intensity of the photocurable adhesive is appropriately determined depending on the composition of the photocurable adhesive, and is not particularly limited, but the irradiation intensity in a wavelength region effective for activation of the polymerization initiator is 0.1. It is preferably up to 6000 mW/cm 2 . When the irradiation intensity is 0.1 mW/cm 2 or more, the reaction time does not become too long, and when it is 6000 mW/cm 2 or less, heat generated from the light source and heat generated by hardening of the photocurable adhesive are less likely to occur. The resulting yellowing of the epoxy resin or degradation of the polarizing film. The light irradiation time of the photocurable adhesive is controlled by a photocurable adhesive which is to be cured, and is not particularly limited, but is preferably set to a cumulative amount of light expressed by the product of the irradiation intensity and the irradiation time. It is 10 to 10000 mJ/cm 2 . When the cumulative light amount of the photocurable adhesive is 10 mJ/cm 2 or more, the active species derived from the polymerization initiator can be produced in a sufficient amount to make the hardening reaction more sure, and when it is 10000 mJ/cm 2 or less, The irradiation time does not become too long, and good productivity can be maintained. Further, the thickness of the adhesive layer after the irradiation of the active energy ray is usually about 0.001 to 5 μm, preferably 0.01 μm or more, more preferably 2 μm or less, still more preferably 1 μm or less.

當藉由照射活性能量線而使光硬化型接著劑硬化時，較佳係在不會使偏光薄膜之偏光度、透射率及色相等偏光板之諸功能下降的條件下進行硬化。 When the photocurable adhesive is cured by irradiation of the active energy ray, it is preferably cured without lowering the functions of the polarizing film, the transmittance, and the color of the polarizing plate.

當將薄膜積層於偏光薄膜之雙面時，若藉由接著劑層而進行積層，則薄膜係以透明保護薄膜為佳。 When the film is laminated on both surfaces of the polarizing film, if the film is laminated by the adhesive layer, the film is preferably a transparent protective film.

透明保護薄膜可列舉如環烯烴系樹脂薄膜、乙酸纖維素系樹脂薄膜、聚對苯二甲酸乙二酯(polyethylene terephthalate)或聚苯二甲酸乙二酯、聚對苯二甲酸丁二酯等聚酯系樹脂薄膜、聚碳酸酯系樹脂薄膜、丙烯酸系樹脂薄膜、聚丙烯系樹脂薄膜等該領域中以往至今所廣泛使用之薄膜。 Examples of the transparent protective film include a cycloolefin resin film, a cellulose acetate resin film, polyethylene terephthalate, polyethylene terephthalate, and polybutylene terephthalate. A film which has been widely used in the past, such as an ester resin film, a polycarbonate resin film, an acrylic resin film, and a polypropylene resin film.

環烯烴系樹脂可使用適當之市售品，例如Topas(Ticona公司製)、ARTON(JSR(股)製)、ZEONOR(日本ZEON(股)製)、ZEONEX(日本ZEON(股)製)、APEL(三井化學(股)製)。當將此等環烯烴系樹脂予以製膜而製成薄膜時，適宜使用溶劑澆鑄法、熔融擠壓法等公知之方法。此外，亦可使用例如S-SINA(積水化學工業(股)製)、SCA40(積水化學工業(股)製)、ZEONOR薄膜((股)OPTES製)等預先經製膜之環烯烴系樹脂製薄膜之市售品。 For the cycloolefin-based resin, a commercially available product such as Topas (manufactured by Ticona Co., Ltd.), ARTON (manufactured by JSR Co., Ltd.), ZEONOR (manufactured by Japan ZEON Co., Ltd.), ZEONEX (manufactured by Japan ZEON Co., Ltd.), and APEL can be used. (Mitsui Chemical Co., Ltd.). When the cycloolefin-based resin is formed into a film to form a film, a known method such as a solvent casting method or a melt extrusion method is preferably used. In addition, it is also possible to use, for example, S-SINA (made by Sekisui Chemical Co., Ltd.), SCA40 (made by Sekisui Chemical Co., Ltd.), ZEONOR film (made by OPTES), etc. Commercially available film.

環烯烴系樹脂薄膜亦可為經單軸延伸或二軸延伸者。藉由進行延伸，即可對於環烯烴系樹脂薄膜賦予任意之相位差值。延伸通常係將薄膜一邊從捲筒拉出一邊連續地進行，並在加熱爐中，朝輥之進行方向、或與該進行方向垂直之方向、或該兩方向進行延伸。加熱爐之溫度通常係採 用環烯烴系樹脂之玻璃轉移溫度附近至玻璃轉移溫度+100℃之範圍。延伸之倍率通常為1.1至6倍、較佳為1.1至3.5倍。 The cycloolefin-based resin film may also be a uniaxially stretched or biaxially stretched one. By extending, any phase difference value can be imparted to the cycloolefin resin film. The stretching is usually carried out continuously while pulling the film out of the roll, and in the heating furnace, extending in the direction in which the roll is performed, in the direction perpendicular to the direction of progress, or in both directions. The temperature of the furnace is usually taken The range from the vicinity of the glass transition temperature of the cycloolefin resin to the glass transition temperature + 100 °C. The stretching ratio is usually 1.1 to 6 times, preferably 1.1 to 3.5 times.

當環烯烴系樹脂薄膜係經延伸者時，其延伸方向為任意，但一般相對於薄膜之流動方向為0°、45°、90°者。延伸方向為0°之薄膜之相位差特性為完全單軸性，45°、90°之薄膜之相位差特性常帶有微弱之二軸性。該特性會影響顯示裝置之視角，但只要依據適用之液晶顯示裝置之類型或複合偏光板之類型而適當選擇即可。相位差值常使用於通常被稱為λ/4、λ/2等者，若為λ/4則常為90至170nm之相位差範圍，若為λ/2則常為200至300nm之相位差範圍。 When the cycloolefin-based resin film is stretched, its extending direction is arbitrary, but generally it is 0°, 45°, or 90° with respect to the flow direction of the film. The phase difference characteristic of the film in which the stretching direction is 0° is completely uniaxial, and the phase difference characteristic of the film of 45° and 90° often has a weak biaxiality. This characteristic affects the viewing angle of the display device, but may be appropriately selected depending on the type of the liquid crystal display device to be used or the type of the composite polarizing plate. The phase difference is often used in what is commonly referred to as λ/4, λ/2, etc., and λ/4 is often a phase difference range of 90 to 170 nm, and if λ/2 is often a phase difference of 200 to 300 nm. range.

當環烯烴系樹脂薄膜為滾筒狀態時，由於薄膜有彼此接著而容易發生結塊(blocking)之傾向，故通常會貼合防護薄膜而作成捲筒狀。此外，由於環烯烴系樹脂薄膜一般係表面活性不佳，故以對於要與偏光薄膜接著之表面進行電漿處理、電暈處理、紫外線照射處理、火焰(flame)處理、皂化處理等表面處理為佳。其中，以可較容易實施之電漿處理、電暈處理為適宜。 When the cycloolefin-based resin film is in a roll state, the film tends to block due to the subsequent adhesion of the film. Therefore, the protective film is usually bonded to the roll to be formed into a roll shape. In addition, since the cycloolefin-based resin film generally has poor surface activity, surface treatment such as plasma treatment, corona treatment, ultraviolet irradiation treatment, flame treatment, saponification treatment, etc., is performed on the surface to be bonded to the polarizing film. good. Among them, plasma treatment and corona treatment which are relatively easy to implement are suitable.

可用於作為透明保護薄膜之乙酸纖維素系樹脂，係纖維素之部分或完全之乙酸酯化物，可列舉如三乙醯基纖維素、二乙醯基纖維素、纖維素乙酸酯丙酸酯等。 A cellulose acetate-based resin which can be used as a transparent protective film, which is a partial or complete acetate ester of cellulose, and examples thereof include triethyl fluorenyl cellulose, diethyl acetyl cellulose, cellulose acetate propionic acid. Ester and the like.

此等纖維素酯系樹脂之薄膜可使用適宜之市售品，例如Fujitac TD80(富士薄膜(股)製)、Fujitac TD80UF(富 士薄膜(股)製)、Fujitac TD80UZ(富士薄膜(股)製)、KC8UX2M(Konica Minolta Opto(股)製)、KC4UY(Konica Minolta Opto(股)製)等。 A film of such a cellulose ester resin can be suitably used, for example, Fujitac TD80 (Fuji Film Co., Ltd.), Fujitac TD80UF (rich). , Ltd., manufactured by Fujifilm Co., Ltd., Fujitec TD80UZ (manufactured by Fujifilm Co., Ltd.), KC8UX2M (manufactured by Konica Minolta Opto Co., Ltd.), KC4UY (manufactured by Konica Minolta Opto Co., Ltd.), and the like.

此外，亦可使用經賦予相位差特性之乙酸纖維素系樹脂薄膜，該經賦予相位差特性之乙酸纖維素系樹脂薄膜之市售品可列舉如WV BZ 438(富士薄膜(股)製)、KC4FR-1(Konica Minolta Opto(股)製)等。乙酸纖維素既可稱為乙醯基纖維素、亦可稱為纖維素乙酸酯。 In addition, a cellulose acetate-based resin film to which a phase difference property is imparted may be used, and a commercially available product of the cellulose acetate-based resin film to which the phase difference property is imparted may be, for example, WV BZ 438 (manufactured by Fuji Film Co., Ltd.). KC4FR-1 (manufactured by Konica Minolta Opto Co., Ltd.) and the like. Cellulose acetate can be referred to as acetaminocellulose or cellulose acetate.

纖維素系樹脂薄膜尤其是在使用水系接著劑而與偏光薄膜積層時，為了提高與偏光薄膜之接著性，而施行皂化處理。皂化處理可採用浸漬在氫氧化鈉或氫氧化鉀等鹼性水溶液中之方法。 In particular, when a layered film is laminated with a polarizing film using a water-based adhesive, the cellulose resin film is subjected to a saponification treatment in order to improve adhesion to the polarizing film. The saponification treatment may be carried out by immersing in an alkaline aqueous solution such as sodium hydroxide or potassium hydroxide.

對於環烯烴系樹脂薄膜、乙酸纖維素系樹脂薄膜之表面，亦可因應用途而施行防眩(antiglare)處理、硬塗層(hard coat)處理、抗靜電處理、抗反射處理等表面處理。又，為了改善視角特性，亦可形成液晶層等。 The surface of the cycloolefin resin film or the cellulose acetate resin film may be subjected to surface treatment such as antiglare treatment, hard coat treatment, antistatic treatment, and antireflection treatment depending on the application. Further, in order to improve the viewing angle characteristics, a liquid crystal layer or the like may be formed.

在將薄膜積層於偏光薄膜之雙面時，薄膜係以至少一面為透濕度低之樹脂薄膜者為佳。透濕度若低，則容易在積層並賦予高溫時使偏光薄膜保持於高濕度環境下。 When the film is laminated on both sides of the polarizing film, the film is preferably one having a resin film having a low moisture permeability on at least one side. If the moisture permeability is low, it is easy to maintain the polarizing film in a high humidity environment when laminating and imparting high temperature.

較佳之透濕度係指在40℃、90%RH環境下為400(g/m2‧24hr)以下，更佳為300g以下，特佳為100g以下，最佳為50g以下。 The preferred moisture permeability is 400 (g/m 2 ‧24 hr) or less, more preferably 300 g or less, particularly preferably 100 g or less, and most preferably 50 g or less in an environment of 40 ° C and 90% RH.

當透明保護薄膜為捲筒狀態時，由於薄膜有彼此接著而容易發生結塊之傾向，故通常係使用在捲筒端部施行凹 凸加工、或在端部中***帶狀物(ribbon)、或貼合防護薄膜而製成之捲筒狀物。 When the transparent protective film is in a roll state, since the film tends to agglomerate when it is followed by each other, it is usually used to perform concave at the end of the roll. A roll made by convex processing, or by inserting a ribbon in the end or by fitting a protective film.

透明保護薄膜之厚度以較薄者為佳，但若太薄則會使強度降低且使加工性不佳。另一方面，若太厚，則會發生使透明性降低、或使積層後所需之熟化時間變長等問題。因此，透明保護薄膜之適當厚度為例如5至200μm，較佳為10至150μm、更佳為20至100μm。 The thickness of the transparent protective film is preferably as thin as possible, but if it is too thin, the strength is lowered and the workability is poor. On the other hand, if it is too thick, there arises a problem that transparency is lowered or the aging time required after lamination is lengthened. Therefore, a suitable thickness of the transparent protective film is, for example, 5 to 200 μm, preferably 10 to 150 μm, more preferably 20 to 100 μm.

在偏光薄膜之雙面直接積層薄膜時，薄膜係以可剝離之防護薄膜為佳。防護薄膜係在例如於偏光板之偏光薄膜面形成黏著劑層時等不再需要之階段予以剝離。 When the film is directly laminated on both sides of the polarizing film, the film is preferably a peelable protective film. The pellicle film is peeled off at a stage where it is no longer necessary, for example, when an adhesive layer is formed on the surface of the polarizing film of the polarizing plate.

防護薄膜與偏光薄膜之間之剝離力為0.01至5N/25mm，較佳為0.01至2N/25mm，更佳為0.01至0.5N/25mm。剝離力未達0.01N/25mm時，由於偏光薄膜與防護薄膜之密著力小，故有時會發生防護薄膜之部分性剝離。此外，剝離力超過5N/25mm時，由於會難以從偏光薄膜剝離防護薄膜，故為不佳。 The peeling force between the protective film and the polarizing film is from 0.01 to 5 N/25 mm, preferably from 0.01 to 2 N/25 mm, more preferably from 0.01 to 0.5 N/25 mm. When the peeling force is less than 0.01 N/25 mm, since the adhesion between the polarizing film and the protective film is small, partial peeling of the protective film may occur. Further, when the peeling force exceeds 5 N/25 mm, it is difficult to peel off the protective film from the polarizing film, which is not preferable.

就防護薄膜之材質而言，可適合使用容易處理且確保某種程度之透明性的聚乙烯系樹脂、聚丙烯系樹脂、聚苯乙烯系樹脂、聚對苯二甲酸乙二酯系樹脂等，可使用將此等之1種或2種以上成形為單層或多層狀之薄膜作為保護薄膜。 As the material of the protective film, a polyethylene resin, a polypropylene resin, a polystyrene resin, a polyethylene terephthalate resin, or the like which is easy to handle and which ensures a certain degree of transparency can be suitably used. A film in which one type or two or more types are formed into a single layer or a plurality of layers can be used as the protective film.

就如此之防護薄膜而言，具體上可列舉如：在聚乙烯樹脂薄膜表面形成有黏著劑層之sunytect(Sun-A化研(股)販售)、在聚對苯二甲酸乙二酯樹脂薄膜表面形成有黏著劑 層之E-mask(日東電工(股)製)、在聚對苯二甲酸乙二酯樹脂薄膜表面形成有黏著劑層之Mastack(藤森工業(股)製)等市售品。 In the case of such a protective film, for example, sunytect (sold by Sun-A Chemical Research Co., Ltd.) in which an adhesive layer is formed on the surface of a polyethylene resin film, and polyethylene terephthalate resin are mentioned. An adhesive is formed on the surface of the film A commercially available product such as Mastack (manufactured by Fujimori Industrial Co., Ltd.) in which an adhesive layer is formed on the surface of a polyethylene terephthalate resin film.

其中，單獨對於偏光薄膜具有黏著性之自行黏著性之防護薄膜由於不須保護防護薄膜表面之黏著劑層而為簡便，故可更適合使用。上述對於偏光薄膜顯示適當剝離力之自行黏著性樹脂薄膜之市售品可列舉如由聚乙烯樹脂所構成之Toretec(東麗(股)製)等。 Among them, the self-adhesive protective film which has adhesiveness to the polarizing film alone is simple and suitable for use because it does not need to protect the adhesive layer on the surface of the protective film. The commercially available product of the self-adhesive resin film which exhibits a suitable peeling force for the polarizing film is, for example, Toretec (manufactured by Toray Industries, Inc.) made of a polyethylene resin.

又，透明保護薄膜係以魚眼(fisheye)等缺陷較少者為佳。若有缺陷，則有時會轉印形狀至偏光薄膜而成為偏光薄膜之缺陷。 Further, the transparent protective film is preferably one having fewer defects such as fisheye. If there is a defect, the shape may be transferred to the polarizing film to become a defect of the polarizing film.

依上述而製造之偏光板，亦可將具有偏光板以外之光學機能之光學薄膜積層於該偏光板之保護薄膜面或黏著劑層面。該光學薄膜之例可列舉如：在基材表面塗佈液晶性化合物並經定向之光學補償薄膜、透射某種偏振光並反射顯示與其相反性質之偏振光的反射型偏光薄膜、由聚碳酸酯系樹脂所構成之相位差薄膜、由環狀聚烯烴系樹脂所構成之相位差薄膜、在表面具有凹凸形狀之附有防眩機能之薄膜、附有表面抗反射機能之薄膜、表面具有反射機能之反射薄膜、兼具反射機能與透射機能之半透射反射薄膜等。與在基材表面塗佈有液晶性化合物並經定向之光學補償薄膜相當的市售品，可列舉如WV薄膜(富士薄膜(股)製)、NH薄膜(新日本石油(股)製)、NR薄膜(新日本石油(股)製)等。與會透射某種偏振光並反射顯示與其相反性質之偏 振光的反射型偏光薄膜相當之市售品，可列舉如DBEF(3M公司製，於日本可由住友3M(股)獲得)、APF(3M公司製，於日本可由住友3M(股)獲得)等。此外，與由環狀聚烯烴系樹脂所構成之相位差薄膜相當的市售品，可列舉如ARTON薄膜(JSR(股)製)、S-SINA(積水化學工業(股)製)、ZEONOR薄膜((股)OPTES製)等。 In the polarizing plate manufactured as described above, an optical film having an optical function other than the polarizing plate may be laminated on the protective film surface or the adhesive layer of the polarizing plate. Examples of the optical film include a liquid crystal compound coated on the surface of the substrate and an optical compensation film oriented, a polarized polarizing film that transmits a polarized light and reflects polarized light having a property opposite thereto, and a polycarbonate film. A retardation film made of a resin, a retardation film made of a cyclic polyolefin resin, a film having an anti-glare function having an uneven shape on the surface, a film having a surface anti-reflection function, and a surface having a reflection function A reflective film, a transflective film having both a reflective function and a transmissive function. The commercially available product which is equivalent to the optical compensation film which is coated with the liquid crystal compound on the surface of the substrate, and the like, may be, for example, a WV film (manufactured by Fuji Film Co., Ltd.) or an NH film (manufactured by Nippon Oil Co., Ltd.). NR film (manufactured by Nippon Oil Co., Ltd.) and the like. The meeting transmits a certain polarized light and reflects the opposite nature of the opposite A commercially available product of a radiant reflective polarizing film is exemplified by DBEF (manufactured by 3M Company, available from Sumitomo 3M (share) in Japan), APF (made by 3M Company, available from Sumitomo 3M (share) in Japan), etc. . In addition, as a commercial product corresponding to a retardation film made of a cyclic polyolefin resin, for example, an ARTON film (manufactured by JSR Co., Ltd.), S-SINA (manufactured by Sekisui Chemical Co., Ltd.), and a ZEONOR film are mentioned. ((share) OPTES system) and so on.

將此等其他光學薄膜設置於上述偏光板之保護薄膜側時，通常兩者係藉由黏著劑而積層。此時之黏著劑可使用與上述所說明者相同者，但其貯藏彈性模數(storage elastic modulus)亦可不需那麼大。此外，將其他光學薄膜設置於上述偏光板之黏著劑層側時，光學薄膜係藉由該黏著劑層而接著。此時，一般係在該光學薄膜之外側設置用以貼合至液晶單元的黏著劑層。 When these other optical films are provided on the protective film side of the polarizing plate, they are usually laminated by an adhesive. The adhesive at this time may be the same as those described above, but the storage elastic modulus may not be so large. Further, when another optical film is provided on the side of the adhesive layer of the polarizing plate, the optical film is followed by the adhesive layer. At this time, an adhesive layer for bonding to the liquid crystal cell is generally provided on the outer side of the optical film.

依本發明之製造方法而製造之附有黏著劑層之偏光板通常具有大型之捲筒材料或薄片(sheet)材料之形態，為了獲得具有所期望之形狀與透射軸的偏光板，而以具備銳利刀刃之裁切工具進行裁切((切片)chip cut)。因此，在經裁切而獲得之偏光板小片(chip)，會在外周端部產生偏光薄膜露出至外部的狀態。 The polarizing plate with an adhesive layer manufactured by the manufacturing method of the present invention usually has a large roll material or a sheet material, and is provided with a polarizing plate having a desired shape and a transmission axis. The cutting tool of the sharp blade is cut (chip cut). Therefore, in the polarizing plate chip obtained by the cutting, a state in which the polarizing film is exposed to the outside is generated at the outer peripheral end portion.

將此狀態之偏光板小片實施例如熱衝擊試驗等耐久性試驗時，相較於一般所使用之偏光板、亦即將偏光薄膜之雙面以纖維素系樹脂薄膜等加以保護之偏光板，有容易發生剝離或破裂等不良情況之傾向。為了避免此等不良情況，本發明所得之偏光板小片係以依據飛切法(fly cutting method)等將外周端面連續地削切為佳。 When the polarizing plate of this state is subjected to a durability test such as a thermal shock test, it is easy to use a polarizing plate which is generally used, that is, a polarizing plate which is protected by a cellulose resin film or the like on both sides of the polarizing film. There is a tendency to cause problems such as peeling or cracking. In order to avoid such adverse conditions, the polarizing plate piece obtained by the present invention is based on the fly cutting method (fly Cutting method) or the like is preferably performed by continuously cutting the outer peripheral end surface.

(偏光板之對於液晶單元之貼合) (Positive to the liquid crystal cell of the polarizing plate)

依上述製造方法而製造之偏光板係藉由黏著劑層而貼合於液晶顯示裝置之液晶單元。 The polarizing plate manufactured by the above manufacturing method is bonded to the liquid crystal cell of the liquid crystal display device by an adhesive layer.

如此之黏著劑層一般係使用由以往用於貼合液晶單元與偏光板的各種黏著劑，例如丙烯酸系、橡膠系、胺酯系、聚矽氧(silicone)系、聚乙烯醚等之黏著劑所形成者。此外，亦可使用能量線硬化型、熱硬化型之黏著劑，其中較佳係以透明性、耐候性、耐熱性等優異之丙烯酸系樹脂作為基礎聚合物(base polymer)而成的丙烯酸系黏著劑。 Such an adhesive layer generally uses various adhesives conventionally used for laminating a liquid crystal cell and a polarizing plate, for example, an adhesive such as an acrylic, a rubber, an amine ester, a silicone, or a polyvinyl ether. Formed by. Further, an energy ray-curable or thermosetting type adhesive may be used. Among them, an acrylic resin which is excellent in transparency, weather resistance, heat resistance, and the like as a base polymer is preferably used. Agent.

當黏著劑層直接形成於偏光薄膜表面時，以在23至80℃之溫度範圍中具有0.15至1MPa之貯藏彈性模數者為佳，在其他情形下則亦可為不具有如此高之彈性模數者。 When the adhesive layer is directly formed on the surface of the polarizing film, it is preferably one having a storage elastic modulus of 0.15 to 1 MPa in a temperature range of 23 to 80 ° C, and in other cases, an elastic modulus having such a high modulus. Number.

丙烯酸系黏著劑並無特別限制，係適合使用(甲基)丙烯酸丁酯、(甲基)丙烯酸乙酯、(甲基)丙烯酸異辛酯、(甲基)丙烯酸2-乙基己酯等(甲基)丙烯酸酯系基礎聚合物、或是使用2種以上此等(甲基)丙烯酸酯等的共聚合系基礎聚合物。再者，此等基礎聚合物中係共聚合有極性單體。極性單體可列舉如(甲基)丙烯酸、(甲基)丙烯酸2-羥基丙酯、(甲基)丙烯酸羥基乙酯、(甲基)丙烯醯胺、(甲基)丙烯酸N,N-二甲基胺基乙酯、(甲基)丙烯酸縮水甘油酯等具有羧基、羥基、醯胺基、胺基、環氧基等官能基之單體。 The acrylic adhesive is not particularly limited, and is preferably butyl (meth)acrylate, ethyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, or the like ( A methylated acrylate based base polymer or a copolymerized base polymer of two or more such (meth) acrylates. Further, these base polymers are copolymerized with a polar monomer. Examples of the polar monomer include (meth)acrylic acid, 2-hydroxypropyl (meth)acrylate, hydroxyethyl (meth)acrylate, (meth)acrylamide, and N,N-di(meth)acrylate. A monomer having a functional group such as a carboxyl group, a hydroxyl group, a decylamino group, an amine group or an epoxy group, such as methylaminoethyl ester or glycidyl (meth)acrylate.

此等丙烯酸系黏著劑當然可單獨使用，但通常係併用交聯劑。交聯劑可例示如：屬於2價或多價之金屬鹽，且 與羧基形成羧酸金屬鹽者；屬於多元胺化合物，且與羧基形成醯胺鍵者；屬於聚環氧化合物或多元醇化合物，且與羧基形成酯鍵者；屬於聚異氰酸酯化合物，且與羧基形成醯胺鍵者等。其中，聚異氰酸酯化合物係廣泛地使用於作為有機系交聯劑。 These acrylic adhesives can of course be used singly, but usually a crosslinking agent is used in combination. The crosslinking agent can be exemplified by a metal salt belonging to divalent or polyvalent, and a metal salt of a carboxylic acid with a carboxyl group; a polyamine compound and a guanamine bond with a carboxyl group; a polyepoxide or a polyol compound, and an ester bond with a carboxyl group; a polyisocyanate compound and formed with a carboxyl group Amidoxime bond etc. Among them, polyisocyanate compounds are widely used as organic crosslinking agents.

能量線硬化型黏著劑係指具有受到紫外線或電子線等能量線之照射而硬化之性質，並具有即使在照射能量線前亦具有黏著性而密著於薄膜等被黏著體，且具有可藉照射能量線而硬化以調整密著力之性質的黏著劑。能量線硬化型黏著劑尤以使用紫外線硬化型黏著劑為特佳。能量線硬化型黏著劑一般係以丙烯酸系黏著劑與能量線聚合性化合物作為主成分。通常會另調配有交聯劑，並且，亦可因應需要而調配光聚合起始劑或光敏劑。 The energy ray-curable adhesive refers to a property which is hardened by irradiation with an energy ray such as an ultraviolet ray or an electron beam, and has an adhesive property even before being irradiated with an energy ray, and is adhered to an adherend such as a film. An adhesive that is irradiated with an energy ray and hardened to adjust the nature of the adhesion. The energy ray-curable adhesive is particularly preferably an ultraviolet curable adhesive. The energy ray-curable adhesive generally has an acrylic adhesive and an energy ray polymerizable compound as a main component. A crosslinking agent is usually additionally provided, and a photopolymerization initiator or a photosensitizer may be formulated as needed.

在黏著劑組成物中，除了上述基礎聚合物及交聯劑以外，因應需要，亦可為了調整黏著劑之黏著力、凝集力、黏性、彈性模數、玻璃轉移溫度等，而調配例如天然物或合成物之樹脂類、賦予黏著性之樹脂、抗氧化劑、紫外線吸收劑、染料、顏料、消泡劑、腐蝕抑制劑、光聚合起始劑等適宜之添加劑。亦可復含有微粒子而製成顯示光散射性之黏著劑層。 In the adhesive composition, in addition to the above-mentioned base polymer and cross-linking agent, if necessary, in order to adjust the adhesive adhesion, cohesive force, viscosity, elastic modulus, glass transition temperature, etc., for example, natural Suitable additives such as resins for resins or compositions, resins for imparting adhesion, antioxidants, ultraviolet absorbers, dyes, pigments, antifoaming agents, corrosion inhibitors, photopolymerization initiators, and the like. The microparticles may be further contained to form a light-scattering adhesive layer.

黏著劑層之厚度係以1至40μm為佳，但為了獲得本發明之目的之薄型偏光板，在不損及加工性、耐久性之特性的範圍內，以塗成較薄為佳，從保持良好加工性且抑制偏光子之尺寸變化之觀點來看，以3至25μm為更佳。黏 著劑層若太薄則黏著劑會降低，若太厚則黏著性會容易發生溢出等不良情況。 The thickness of the adhesive layer is preferably from 1 to 40 μm. However, in order to obtain the thin polarizing plate for the purpose of the present invention, it is preferable to coat thinner in a range that does not impair the properties of workability and durability. From the viewpoint of good processability and suppression of dimensional change of the polarizer, it is more preferably 3 to 25 μm. sticky If the coating layer is too thin, the adhesive will be lowered, and if it is too thick, the adhesion will easily overflow and the like.

直接形成於偏光薄膜表面之黏著劑係如上所述，23至80℃之溫度範圍中之貯藏彈性模數係以皆為0.15至1MPa為較佳。在通常之圖像顯示裝置或其所用之光學薄膜中所使用的感壓接著劑之貯藏彈性模數至多為0.1MPa左右，相較於此，本發明所用之黏著劑之較佳之貯藏彈性模數高達0.15至1MPa。又，貯藏彈性模數可使用市售之黏彈性測定裝置，例如DYNAMIC ANALYZER RDA II(REOMETRIC公司製)而測定。 The adhesive directly formed on the surface of the polarizing film is as described above, and the storage elastic modulus in the temperature range of 23 to 80 ° C is preferably 0.15 to 1 MPa. The storage elastic modulus of the pressure-sensitive adhesive used in the conventional image display device or the optical film used therein is at most about 0.1 MPa, and the storage elastic modulus of the adhesive used in the present invention is better than this. Up to 0.15 to 1 MPa. Further, the storage elastic modulus can be measured using a commercially available viscoelasticity measuring device such as DYNAMIC ANALYZER RDA II (manufactured by REOMETRIC Co., Ltd.).

又，本發明之偏光板之製造方法中，將黏著劑層形成於偏光薄膜之方法並無特別限制，可在偏光薄膜之另一面塗佈含有以上述基礎聚合物為首之各成分的溶液並乾燥而形成黏著劑層後，將經施行聚矽氧系等之脫模處理的脫離膜層(separator)予以積層而獲得，亦可在脫離膜層上形成黏著劑層後，轉印至偏光薄膜並進行積層。此外，將黏著劑層形成於偏光薄膜時，亦可因應需要而對偏光薄膜及黏著劑層之至少一方進行密著處理、例如電暈處理等。又，所形成之黏著劑層之表面通常係經已施行脫模處理之脫離膜所保護，並在此偏光板貼合至液晶單元或其他光學薄膜等之前，先剝離該脫離膜。 Further, in the method for producing a polarizing plate of the present invention, the method of forming the adhesive layer on the polarizing film is not particularly limited, and a solution containing each component including the above-mentioned base polymer may be applied to the other surface of the polarizing film and dried. After the adhesive layer is formed, a release layer obtained by performing a release treatment such as polyoxymethylene or the like is laminated, and an adhesive layer may be formed on the release film layer, and then transferred to a polarizing film. Carry out the layering. Further, when the adhesive layer is formed on the polarizing film, at least one of the polarizing film and the adhesive layer may be subjected to a close treatment such as corona treatment or the like as needed. Further, the surface of the formed adhesive layer is usually protected by a release film which has been subjected to a release treatment, and the release film is peeled off before the polarizing plate is attached to a liquid crystal cell or other optical film or the like.

(實施例) (Example)

以下，茲顯示實施例及比較例以具體說明本發明，但本發明不受此等例所限定。 Hereinafter, the present invention will be specifically described by way of examples and comparative examples, but the present invention is not limited by these examples.

[實施例1] [Example 1]

(偏光薄膜之製作) (production of polarizing film)

將平均聚合度約2400、皂化度99.9莫耳%以上且厚度75μm之聚乙烯醇薄膜以乾式進行單軸延伸成約5倍，並在保持緊張狀態下浸漬於60℃之純水中1分鐘後，在碘/碘化鉀/水之重量比為0.1/5/100之水溶液中於28℃浸漬60秒。然後，在碘化鉀/硼酸/水之重量比為10.5/7.5/100之水溶液中於72℃浸漬300秒。繼而，以10℃之純水洗淨5秒後，在保持400N之張力的狀態下，以60℃乾燥75秒、再以75℃乾燥30秒，而獲得水分率為10.9%之吸附定向有碘之偏光薄膜。 A polyvinyl alcohol film having an average polymerization degree of about 2400, a degree of saponification of 99.9 mol% or more and a thickness of 75 μm was uniaxially stretched to about 5 times in a dry manner, and immersed in pure water at 60 ° C for 1 minute while being kept under tension. The mixture was immersed in an aqueous solution of iodine/potassium iodide/water in a weight ratio of 0.1/5/100 at 28 ° C for 60 seconds. Then, it was immersed at 72 ° C for 300 seconds in an aqueous solution of potassium iodide / boric acid / water in a weight ratio of 10.5 / 7.5 / 100. Then, after washing with pure water of 10 ° C for 5 seconds, the film was dried at 60 ° C for 75 seconds and then dried at 75 ° C for 30 seconds while maintaining a tension of 400 N to obtain an adsorption oriented iodine having a moisture content of 10.9%. Polarized film.

(接著劑之調製) (adhesive modulation)

另外，在100重量份之水中溶解羧基改質聚乙烯醇(Kuraray poval KL318(Kuraray(股)製)3重量份、水溶性聚醯胺環氧樹脂(Sumirez Resin 650(住化CHEMTEX(股)製)(固形分濃度30%之水溶液)1.5重量份，調製成以聚乙烯醇系樹脂為主成分之水系接著劑(A)。又，調製羧基改質聚乙烯醇與水溶性聚醯胺環氧樹脂分別為2重量份與1.0重量份之接著劑(B)。 In addition, 3 parts by weight of a carboxy-modified polyvinyl alcohol (Kuraray poval KL318 (manufactured by Kuraray Co., Ltd.), a water-soluble polyamide resin (Sumirez Resin 650 (manufactured by Sumitomo CHEMTEX Co., Ltd.) was dissolved in 100 parts by weight of water. (1.5 parts by weight of an aqueous solution having a solid content of 30%) to prepare a water-based adhesive (A) containing a polyvinyl alcohol-based resin as a main component. Further, a carboxy-modified polyvinyl alcohol and a water-soluble polyamide amine are prepared. The resin was 2 parts by weight and 1.0 part by weight of the adhesive (B), respectively.

(偏光板之製作) (production of polarizing plate)

在先前所得之偏光薄膜之一面，使用上述接著劑(A)將經施行皂化處理之由三乙醯基纖維素所構成之厚度40μm之薄膜(KC4UY，Konica Minolta Opto(股)製)藉由軋輥而貼合，又，在另一面，使用上述接著劑(B)將預先經施行 電暈處理之降冰片烯(norbornene)系樹脂製之相位差薄膜(ZEONOR薄膜ZD14-141158-A1340(OPTES(股)製)，厚度：32μm)藉由軋輥而貼合。一邊使貼合物之張力保持於430N/m，一邊於室溫進行貼合，在經過5秒後，依序於60℃以11秒、於80℃以141秒、於70℃以93秒連續地進行乾燥，而獲得偏光板。 On the surface of the previously obtained polarizing film, a 40 μm-thick film (KC4UY, manufactured by Konica Minolta Opto Co., Ltd.) composed of triethylsulfonyl cellulose which has been subjected to saponification treatment using the above-mentioned adhesive (A) is passed through a roll. And the fit, and, on the other hand, the use of the above adhesive (B) will be carried out in advance A phase difference film made of corona-treated norbornene resin (ZEONOR film ZD14-141158-A1340 (manufactured by OPTES), thickness: 32 μm) was bonded by a roll. While maintaining the tension of the laminate at 430 N/m, it was bonded at room temperature, and after 5 seconds, it was sequentially continued at 60 ° C for 11 seconds, at 80 ° C for 141 seconds, and at 70 ° C for 93 seconds. Drying was carried out to obtain a polarizing plate.

[實施例2] [Embodiment 2]

(偏光薄膜之製作) (production of polarizing film)

除了於40℃以60秒、於50℃以25秒進行乾燥以外，其餘與實施例1進行同樣之操作，而獲得水分率為13.9%之偏光薄膜。 The same operation as in Example 1 was carried out except that drying was carried out at 40 ° C for 60 seconds at 50 ° C for 25 seconds to obtain a polarizing film having a moisture content of 13.9%.

(偏光板之製作) (production of polarizing plate)

除了一邊使貼合物之張力維持於430N/m，一邊於室溫下進行貼合，在經過4秒後，依序於60℃以9秒、於80℃以113秒、於70℃以75秒連續地進行乾燥以外，其餘與實施例1進行同樣之操作，而獲得偏光板。 In addition to maintaining the tension of the composition at 430 N/m, the bonding was carried out at room temperature, and after 4 seconds, it was followed by 9 seconds at 60 ° C, 113 seconds at 80 ° C, and 75 at 70 ° C. A polarizing plate was obtained in the same manner as in Example 1 except that the drying was continuously performed in seconds.

[實施例3] [Example 3]

(偏光薄膜之製作) (production of polarizing film)

除了於40℃以60秒、於50℃以25秒進行乾燥以外，其餘與實施例1進行同樣之操作，而獲得水分率為13.9%之偏光薄膜。 The same operation as in Example 1 was carried out except that drying was carried out at 40 ° C for 60 seconds at 50 ° C for 25 seconds to obtain a polarizing film having a moisture content of 13.9%.

(偏光板之製作) (production of polarizing plate)

除了一邊使貼合物之張力維持於430N/m，一邊於室溫下進行貼合，在經過4秒後，依序於60℃以9秒、於90 ℃以39秒、於80℃以74秒、於70℃以75秒連續地進行乾燥以外，其餘與實施例1進行同樣之操作，而獲得偏光板。 In addition to maintaining the tension of the composition at 430 N/m, the bonding was carried out at room temperature, and after 4 seconds, it was sequentially applied at 60 ° C for 9 seconds at 90 °C. The polarizing plate was obtained in the same manner as in Example 1 except that the temperature was continuously dried at 39 ° C for 30 seconds at 80 ° C for 75 seconds.

[比較例1] [Comparative Example 1]

(偏光薄膜之製作) (production of polarizing film)

除了於90℃以106秒進行乾燥以外，其餘與實施例1進行同樣之操作，而獲得水分率為8.7%之偏光薄膜。 The same operation as in Example 1 was carried out except that drying was carried out at 90 ° C for 106 seconds to obtain a polarizing film having a moisture content of 8.7%.

(偏光板之製作) (production of polarizing plate)

除了一邊使貼合物之張力維持於430N/m，一邊於室溫下進行貼合，在經過4秒後，依序於50℃以10秒、於65℃以43秒、於80℃以83秒、於70℃以84秒連續地進行乾燥以外，其餘與實施例1進行同樣之操作，而獲得偏光板。 In addition to maintaining the tension of the composition at 430 N/m, the bonding was carried out at room temperature, and after 4 seconds, it was sequentially applied at 50 ° C for 10 seconds, at 65 ° C for 43 seconds, and at 80 ° C for 83 seconds. A polarizing plate was obtained in the same manner as in Example 1 except that the film was continuously dried at 70 ° C for 84 seconds.

[比較例2] [Comparative Example 2]

(偏光薄膜之製作) (production of polarizing film)

與實施例1進行同樣之操作，而獲得水分率為10.6%之偏光薄膜。 The same operation as in Example 1 was carried out to obtain a polarizing film having a moisture content of 10.6%.

(偏光板之製作) (production of polarizing plate)

除了一邊使貼合物之張力維持於430N/m，一邊於室溫下進行貼合，在經過4秒後，依序於50℃以10秒、於65℃以43秒、於80℃以167秒連續地進行乾燥以外，其餘與實施例1進行同樣之操作，而獲得偏光板。 The film was laminated at room temperature while maintaining the tension of the composition at 430 N/m, and after 10 seconds, it was 10 seconds at 50 ° C, 43 seconds at 65 ° C, and 167 at 80 ° C. A polarizing plate was obtained in the same manner as in Example 1 except that the drying was continuously performed in seconds.

[比較例3] [Comparative Example 3]

(偏光薄膜之製作) (production of polarizing film)

除了於90℃以106秒進行乾燥以外，其餘與實施例1進行同樣之操作，而獲得水分率為8.7%之偏光薄膜。 The same operation as in Example 1 was carried out except that drying was carried out at 90 ° C for 106 seconds to obtain a polarizing film having a moisture content of 8.7%.

(偏光板之製作) (production of polarizing plate)

除了一邊使貼合物之張力維持於430N/m，一邊於室溫下進行貼合，在經過4秒後，依序於50℃以10秒、於70℃以43秒、於80℃以83秒、於90℃以84秒連續地進行乾燥以外，其餘與實施例1進行同樣之操作，而獲得偏光板。 The film was bonded at room temperature while maintaining the tension of the composition at 430 N/m, and after 10 seconds, it was 10 seconds at 50 ° C, 43 seconds at 70 ° C, and 83 at 80 ° C. A polarizing plate was obtained in the same manner as in Example 1 except that the film was continuously dried at 90 ° C for 84 seconds.

[各偏光板之SCR之測定] [Measurement of S CR of each polarizer]

對於上述實施例1至3及比較例1至3所得之偏光板試樣，剝去相位差薄膜，以貼合有實質上不具有相位差特性之三乙醯基纖維素薄膜的狀態下，使用日本分光(股)製之分光光度計(型號：V7100)測定波長450nm、550nm、600nm中之各偏光板之SCR。結果表示於表2。 With respect to the polarizing plate samples obtained in the above Examples 1 to 3 and Comparative Examples 1 to 3, the retardation film was peeled off, and the triethylenesulfonated cellulose film having substantially no phase difference characteristics was bonded thereto, and used. The spectrophotometer (model: V7100) manufactured by Japan Spectrophotometer (S7) measures the S CR of each of the polarizing plates at wavelengths of 450 nm, 550 nm, and 600 nm. The results are shown in Table 2.

(液晶顯示裝置之對比評估) (Comparative evaluation of liquid crystal display devices)

測定某個由白色LED背光與VA型液晶單元所構成之手機模組(不含偏光板之狀態)之發光光譜，並將求得Bmax及Rmax後之結果表示於表1。上述手機模組之Bmax及Rmax係滿足上述式(4)者。在此模組之液晶單元之雙面貼合實施例1至3及比較例1所製作之偏光板，並將組裝有此模組之液晶顯示裝置(手機)之液晶畫面之對比以TOPCON(股)製之分光放射計(SR-UL1)進行測定。結果表示於表2。使用實施例1至3之偏光板的液晶顯示裝置獲得非常良好之對比度，但使用比較例之偏光板的液晶顯示裝置相較於實施 例僅獲得較低之對比度。 The luminescence spectrum of a mobile phone module (without the state of the polarizing plate) composed of a white LED backlight and a VA liquid crystal cell was measured, and the results obtained by obtaining Bmax and Rmax are shown in Table 1. The Bmax and Rmax of the above mobile phone module satisfy the above formula (4). The polarizing plates produced in Embodiments 1 to 3 and Comparative Example 1 are bonded to the double-sided surface of the liquid crystal unit of the module, and the liquid crystal display of the liquid crystal display device (mobile phone) incorporating the module is compared with TOPCON. The spectroradiometer (SR-UL1) manufactured by the system was measured. The results are shown in Table 2. The liquid crystal display device using the polarizing plates of Examples 1 to 3 obtained very good contrast, but the liquid crystal display device using the polarizing plate of the comparative example was compared with the implementation The example only achieves a lower contrast.

(產業上之可利用性) (industrial availability)

本發明之偏光板，即使偏光板單體之視感度校正偏光度(Py)或視感度校正單體透射率(Ty)與以往之偏光板相同，當使用於具有背光及液晶單元(彩色濾光片)之發光波長特性的液晶顯示裝置時，相較於使用以往之偏光板之情形，可使其液晶顯示裝置之畫面之對比大幅上升。 In the polarizing plate of the present invention, even if the polarization correction singlet (Py) or the visual sensitivity correction single transmittance (Ty) of the polarizing plate alone is the same as that of the conventional polarizing plate, when used for having a backlight and a liquid crystal cell (color filter) In the case of a liquid crystal display device having an emission wavelength characteristic, the contrast of the screen of the liquid crystal display device can be greatly increased as compared with the case of using a conventional polarizing plate.

第1圖係表示在CCFL型之背光載置彩色濾光片而測定之發光光譜之一例的曲線圖。 Fig. 1 is a graph showing an example of an emission spectrum measured by mounting a color filter on a CCFL type backlight.

第2圖係表示在LED型之背光載置彩色濾光片而測定之發光光譜之一例的曲線圖。 Fig. 2 is a graph showing an example of an emission spectrum measured by mounting a color filter on an LED type backlight.

第3圖係表示視感度校正曲線之一例的曲線圖。 Fig. 3 is a graph showing an example of a visual sensitivity correction curve.

第4圖係表示以往之偏光板所使用之偏光薄膜之正交透射率光譜的曲線圖。 Fig. 4 is a graph showing the orthogonal transmittance spectrum of a polarizing film used in a conventional polarizing plate.

第5圖係表示本發明之偏光板所使用之偏光薄膜之正交透射率光譜的曲線圖。 Fig. 5 is a graph showing the orthogonal transmittance spectrum of the polarizing film used in the polarizing plate of the present invention.

第6圖係表示與第4圖相同之偏光薄膜之偏光薄膜單體對比的曲線圖。 Fig. 6 is a graph showing the comparison of the polarizing film monomers of the polarizing film which is the same as that of Fig. 4.

第7圖係表示與第5圖相同之偏光薄膜之偏光薄膜單體對比的曲線圖。 Fig. 7 is a graph showing the comparison of the polarizing film monomers of the polarizing film which is the same as that of Fig. 5.

由於本案的圖為實施例的曲線圖，並非本案的代表圖。 Since the diagram of the present case is a graph of the embodiment, it is not a representative diagram of the present case.

故本案無指定代表圖。 Therefore, there is no designated representative map in this case.

Claims (9)

一種偏光板，其係含有在聚乙烯醇系樹脂薄膜吸附定向有二色性色素之偏光薄膜的偏光板，其特徵為：前述偏光薄膜之下述式(1)所定義之波長λ nm中之偏光薄膜單體對比(SCR(λ))係滿足下述式(2)及(3)之關係，SCR(λ)=T//(λ)/T⊥(λ)…(1)(在此，T//(λ)=0.5×[Tp(λ)2+Tc(λ)2]/100 T⊥(λ)=Tp(λ)×Tc(λ)/100 Tp(λ)係以入射之波長λ nm之直線偏光與平行尼科耳鏡(parallel Nicol)的關係而測定之偏光薄膜之透射率(%)，Tc(λ)係以入射之波長λ nm之直線偏光與正交尼科耳鏡(crossed Nicol)的關係而測定之偏光薄膜之透射率(%)，該等皆為以分光光度計進行偏光紫外可見吸收光譜測定所得之測定值)[(SCR(550)+SCR(600))/2]≧30,000…(2) 3,000≦SCR(450)<30,000…(3)。 A polarizing plate comprising a polarizing film in which a polarizing film of a dichroic dye is adsorbed on a polyvinyl alcohol-based resin film, wherein the polarizing film has a wavelength λ nm defined by the following formula (1) The polarizing film monomer comparison (S CR (λ)) satisfies the relationship of the following formulas (2) and (3), S CR (λ) = T // (λ) / T ⊥ (λ) (1) ( Here, T // (λ)=0.5×[Tp(λ) 2 +Tc(λ) 2 ]/100 T ⊥ (λ)=Tp(λ)×Tc(λ)/100 Tp(λ) The transmittance (%) of the polarizing film measured by the linear polarization of the incident wavelength λ nm and the Parallel Nicol, and Tc(λ) is the linear polarization and the orthogonality of the incident wavelength λ nm The transmittance (%) of the polarizing film measured by the relationship of crossed Nicols, which are measured by polarized ultraviolet-visible absorption spectrometry with a spectrophotometer) [(S CR (550)+S CR (600))/2]≧30,000...(2) 3,000≦S CR (450)<30,000...(3). 如申請專利範圍第1項之偏光板，其中，在前述偏光薄膜之一面藉由接著劑層而積層有乙酸纖維素系樹脂薄膜，並在另一面藉由接著劑層而積層有環烯烴系樹脂薄膜者。 The polarizing plate of the first aspect of the invention, wherein a cellulose acetate-based resin film is laminated on one surface of the polarizing film by an adhesive layer, and a cycloolefin resin is laminated on the other surface by an adhesive layer. Film. 如申請專利範圍第1項之偏光板，其中，在前述偏光薄膜之一面藉由接著劑層而積層有乙酸纖維素系樹脂薄膜，並在另一面則積層有可剝離之自行黏著性防護薄膜 者。 The polarizing plate of claim 1, wherein a cellulose acetate-based resin film is laminated on one surface of the polarizing film by an adhesive layer, and a peelable self-adhesive protective film is laminated on the other surface. By. 如申請專利範圍第2或3項之偏光板，其中，前述接著劑層係由水系接著劑所形成者。 The polarizing plate of claim 2, wherein the adhesive layer is formed of a water-based adhesive. 如申請專利範圍第1項之偏光板，其係在含有背光與液晶單元(liquid crystal cell)之液晶顯示裝置中所使用之偏光板，其中，前述液晶顯示裝置係在僅載置液晶單元於前述背光且將背光予以點亮之狀態下測定的光譜中，藍色之發光波峰波長(Bmax)及紅色之發光波峰波長(Rmax)滿足下述式(4)者：-(Rmax-550)<(550-Bmax)…(4)。 The polarizing plate of claim 1, which is a polarizing plate used in a liquid crystal display device including a backlight and a liquid crystal cell, wherein the liquid crystal display device is provided with only a liquid crystal cell In the spectrum measured in a state where the backlight is turned on and the backlight is turned on, the blue light emission peak wavelength (Bmax) and the red light emission peak wavelength (Rmax) satisfy the following formula (4): -(Rmax - 550) < ( 550-Bmax)...(4). 一種申請專利範圍第2項之偏光板之製造方法，其特徵為包含下述步驟：製備在聚乙烯醇系樹脂薄膜吸附定向有二色性色素之偏光薄膜的步驟；以及在水分率9%以上之前述偏光薄膜之一面藉由接著劑層而積層有乙酸纖維素系樹脂薄膜，且在另一面藉由接著劑層而積層有環烯烴系樹脂薄膜，並在剛積層後40秒以內，以70℃以上之溫度進行加熱處理的步驟。 A method for producing a polarizing plate according to the second aspect of the invention, comprising the steps of: preparing a polarizing film in which a dichroic dye is adsorbed on a polyvinyl alcohol-based resin film; and a moisture content of 9% or more A cellulose acetate-based resin film is laminated on one surface of the polarizing film by an adhesive layer, and a cycloolefin-based resin film is laminated on the other surface by an adhesive layer, and within 40 seconds after the layer is laminated, 70 The step of heat treatment at a temperature above °C. 一種申請專利範圍第3項之偏光板之製造方法，其特徵為包含下述步驟：製備在聚乙烯醇系樹脂薄膜吸附定向有二色性色素之偏光薄膜的步驟；以及在水分率9%以上之前述偏光薄膜之一面藉由接著劑層而積層有乙酸纖維素系樹脂薄膜，且在另一面則 積層有可剝離之自行黏著性防護薄膜，並在剛積層後40秒以內，以70℃以上之溫度進行加熱處理的步驟。 A method for producing a polarizing plate according to claim 3, which comprises the steps of: preparing a polarizing film in which a dichroic dye is adsorbed on a polyvinyl alcohol-based resin film; and having a moisture content of 9% or more One side of the polarizing film is laminated with a cellulose acetate resin film by an adhesive layer, and on the other side The step of laminating a self-adhesive protective film and heat-treating at a temperature of 70 ° C or higher within 40 seconds after the layer is laminated. 如申請專利範圍第6或7項之偏光板之製造方法，其中，前述接著劑層係由水系接著劑所形成者。 The method for producing a polarizing plate according to claim 6 or 7, wherein the adhesive layer is formed of a water-based adhesive. 一種液晶顯示裝置，其係含有背光與液晶單元與申請專利範圍第1項的偏光板之液晶顯示裝置，其特徵為：在僅將液晶單元載置於前述背光且將背光予以點亮之狀態下測定的光譜中，藍色之發光波峰波長(Bmax)及紅色之發光波峰波長(Rmax)滿足下述式(4)：(Rmax-550)<(550-Bmax)…(4)。 A liquid crystal display device comprising a backlight and a liquid crystal cell and a liquid crystal display device of the polarizing plate of claim 1 is characterized in that: only the liquid crystal cell is placed on the backlight and the backlight is lit In the measured spectrum, the blue emission peak wavelength (Bmax) and the red emission peak wavelength (Rmax) satisfy the following formula (4): (Rmax - 550) < (550 - Bmax) (4).
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