▁platforms ▁in ▁its ▁follow ▁up , ▁the ▁Power PC ▁ 7 5 0 ▁A K A ▁G 3 . ▁ ▁Im pro ved ▁Li qu id - c ry stal ▁displays , ▁in ▁particular ▁active - matrix ▁T FT ▁( Th in - film ▁trans istor ) ▁L CD ▁technology . ▁Early ▁laptop ▁screens ▁were ▁black ▁and ▁white , ▁blue ▁and ▁white , ▁or ▁gray scale , ▁ST N ▁( Super ▁Tw ist ▁Nem atic ) ▁pass ive - matrix ▁L CD s ▁pr one ▁to ▁heavy ▁sh adows , ▁g host ing ▁and ▁bl ur ry ▁movement ▁( some ▁port able ▁computer ▁screens ▁were ▁sh ar per ▁mon och rome ▁pl asma ▁displays , ▁but ▁these ▁drew ▁too ▁much ▁current ▁to ▁be ▁power ed ▁by ▁batter ies ). ▁ ▁Color ▁ST N ▁screens ▁were ▁used ▁for ▁some ▁time ▁although ▁their ▁view ing ▁quality ▁was ▁poor . ▁ ▁By ▁about ▁ 1 9 9 1 , ▁two ▁new ▁color ▁L CD ▁techn ologies ▁hit ▁the ▁main stream ▁market ▁in ▁a ▁big ▁way ; ▁D ual ▁ST N ▁and ▁T FT . ▁ ▁The ▁D ual ▁ST N ▁screens ▁solved ▁many ▁of ▁the ▁view ing ▁problems ▁of ▁ST N ▁at ▁a ▁very ▁afford able ▁price ▁and ▁the ▁T FT ▁screens ▁offered ▁excellent ▁view ing ▁quality ▁although ▁initially ▁at ▁a ▁ste ep ▁price . ▁ ▁D ST N ▁continued ▁to ▁offer ▁a ▁significant ▁cost ▁advantage ▁over ▁T FT ▁until ▁the ▁mid - 9 0 s ▁before ▁the ▁cost ▁delta ▁dropped ▁to ▁the ▁point ▁that ▁D