6.
已知点\({{F}_{1}}\left( -\sqrt{2},0 \right)\),圆\({{F}_{2}}:{{\left( x-\sqrt{2} \right)}^{2}}+{{y}^{2}}=16\),点\(M\)是圆上一动点,\(M{{F}_{1}}\)的垂直平分线与线段\(M{{F}_{2}}\)交于点\(N\).
\((1)\)求点\(N\)的轨迹方程;
\((2)\)设点\(N\)的轨迹为曲线\(E\),过点\(P\left( 0,1 \right)\)且斜率不为\(0\)的直线\(l\)与\(E\)交于\(A,B\)两点,点\(B\)关于\(y\)轴的对称点为\({B}{{{'}}}\),证明直线\(A{B}{{{'}}}\)过定点,并求\(\Delta PA{B}{{{'}}}\)面积的最大值.