用绝对反射率测量法评价抗反射膜

智能文字提取功能测试中

防反射膜用于多种应用和波长区域；用于可见光区域的窗口和透镜到近红外区域的光通信设备和近红外区域的材料。随着对这些材料的需求和变化，允许的反射率下降到0.1%以下。一个绝对反射率测量配件可以通过改变入射光的入射角度、探测角度或偏振率来评估薄膜的反射率。Application NoteUV-0040 Evaluation of Antireflection Films using an AbsoluteReflectance Measurement Accessory2/5Application Note Evaluation of Antireflection Films using an Absolute Reflectance Measurement Accessor In t ro d uc t ion Antireflect i on f ilms are used f or a var i ety of applications and wave l e n gth regions； for windows a nd l e ns in the visi b le r e gion t o opt i c a l comm u nica t i on devices and materials in the nea r in f r ared region. With th e demand a n d va r ia n ce fo r thes e mate r ials， th e amou nt of reflec ti vity allowable h as dec r eased to l ess t h an 0.1% reflec t ance. An absolu t e ref l ectance measurement accesso r y can b e used to evalu a te the ref l ectance V-770of films by changing the i nc i den t angle， detection angle， or p o l arizat i on of t he in cident ligh t. UV-Visible Spectro p hotomete r In t h is application note， t h e automated absolute r eflectance measurement accessory is used t o measure f ilm s a mples for bot h the visi b le and near -i nf r ared r egio n s with less t han 0.1% reflectance. K eywords V -770/780， U V-Vi sibl e /NIR， A RM N-920/920i Au t o m a t ed A b s o lute Ref le c tance m eas u re m en t accesso ry， Mat e ri a l s ， F il m s Exper i m e ntal The l in ear i ty measurements were o b tai n ed u s i n g 66.7， 133.3， 200.0， and 266.6 mg/L of KMnO solution for the vis ib le region and ND f ilte r A a n d B for t h e i nfrared r egio n. For t h e v i sible r egio n ， the dark measurem e nt i s car ri e d out u s i ng t h e mask in g shield of the cel l hold e r o f the automated absolut e r e fle ct a n c e m e asur e me n t acc e ssory. The bas e lin e m e asur e me n t is obtai n ed using water . For t he i nfrared region ， th e da rk measu re m en t is per f ormed id e n t i cal to th e vis i ble r e gion and t h e bas el ine measurement is obtained wi t h air. T h ree sample measu r eme n t s are p e rformed with t h e filt e rs： ND filt er A set i n the sample holder， with ND f ilter B not paral l el to f i l t er A， and wi th ND f ilt e r B in the sample h o lder . Linearity Measurement Conditions Bandwidth NIR L5.0nm Bandwidth 40.0nm Response 3.84 sec Response 3.84 sec Scan Speed 100 nm/min Scan Speed 100 nm/min Data Interval 1nm Data Interval 1nm T h e reflec ti on mea s urements of three antireflec t ion f ilms with dif f erent co a ti n gs were o b tai n ed us in g the following measurements parameters. The dark measurements were carr i ed out with the mask i ng sh i eld in t h e sample h older . T h e baseline measurement was obtained with a i r and the sample measurements were obtained by placi n g t he samples in th e sample holder . Film Reflectance Measurement Conditions Visible NIR Bandwidth L5.0nm Bandwidth 40 nm (V-770)， 10 nm (V-780) Response 0.96 sec Response 3.84 sec Scan Speed 200 nm/min Scan Speed 100 nm/min Incident Angle 5° Incident Angle 5° Data Interval 0.5nm Data Interval 1nm Polarization N-polarized Polarization N-polarized Re sults The l i n earity measurements of KMnO i n the visible r egion are s h own i n F i gure 1 a n d the calibrat i on curve at 526 nm is shown in Figure 2. In the absorbance r ange from 1 to 4， t h e R2 value i l l ustrates t h e h ighest correlation (more th an 0.999)，indicat i ng the automated absolute r eflectance measurement accessory can obtain absorbances up to 4 AU and therefore transmittance and r eflectance values can be obtained up to 0.01%. JASCO INC. UASGO A ppli c a tio n Lib r ary： htt p：//www.jas co in c .c o m/a pp l icatio n s Figure 1. Ab sor b an c e s p e ctr a o f KMnO s ol u tions . Figure 2. Ca l i br atio n cu rve of KMnO， so l ut ion s obtai n ed a t 526 nm. Figure 3 shows t he absorpt i on spectrum of the ND filters. The spectrum of the i ndividual ND f il ter A and B agrees with the su m of the two filters . T h is also indicates tha t the automated absol u te r eflectance mea s urement accesso r y can obtain absorbances u p to 4 AU and therefo r e transm it tance and ref l ectance values can be obta i n ed up to 0.01%. Figure 3. Ab so r bance s p e ctra o f N D f ilters. 28600 Mary's Cour t ， E a s to n ， M D 21601US A The ant i ref l ect i on films were measured using a V-770 and V-780 and the reflectance data are shown in Figure 4 for the visible region， and the nea r in frared spectra are shown i n F i gu r es 5 and 6. Table 1 provides the ref l ectance val u es of the minima. These f igures illustrate that measu r ements with less than 0.1% re f lec t ance can be obtained in both the visible and near infrared r egions. Figure 4. R ef l e c tanc e sp ect ra o f a n a n ti re fl e c t ion f i l m w it h a v i s ibl e coat i n g . Figure 5. Re fl e c t a n c e sp e ctra of an an tir e fle ctio n fi l m w ith in fr a re d c o a t i n g 1. Figure 6. R e fl ectance spec t ra o f a n a n t i r eflection f i l m wi t h in frar e d co a t in g 2. 28600 Mary's Cour t ， E a s to n ， M D 21601US A Table 1. Mi ni ma r ef l ec t ance va l u e s . AR Coat Vis AR Coat NIR 1 AR Coat NIR 2 Wavelength (nm) Reflectance (%) Wavelength (nm) Reflectance (%) Wavelength (nm) Reflectance (%) V-770 450.5 0.03681 1049 0.03655 1406 0.03703 V-780 1049 0.03655 1406 0.04235 Conclu s io n Th e V-770 a n d V-780 provid e n e a r ly i d e n ti cal sp e ctra i n re ga r ds to t he S/N from 980 to 1140 n m. Howev e r， from 1320 to 1600 nm the V-780 obtains a higher S/N d u e t o th e InGaAs de t ector . T he V-770 i s e qui p ped with a PbS det e cto r which has high sensitivity ove r a wider waveleng t h r ange ， wh i le th e InGaAs detector of t he V-780 h as a h igher se n si t i v ity over a s h ort e r wavel e ng th rang e . T h e V-770 i s th e r e fore suitabl e f or measu r e m e n ts with a wid e wavel e ngth range and the V -780is ideal for h igh se n sitivity measur e me n ts. JASCO INC. 28600 Mary's Cour t ， E a s to n ， M D 21601US A