解:存在.设存在直线l,设其方程为y=x+b,由x^2-2x+4y-4=0y=x+b消去y得2x^2+2(b+1)x+b^2+4b-4=0设a(x1,y1),b(x2,y2)则x1+x2=-b-1,x1x2=(b^2+4b-4)/2y1y2=(x1+b)(x2+b)=x1x2+(x1+x2)b+b^2=(b^2+2b-4)/2由题意得oa⊥ob,把b=1,-4-分别代入方程内,均有△>0,∴b=1,-4满足条件.∴存在满足条件的直线x-y+1=0,x-y+4=0