正方形$\mathit{ABCD}$中，对角线$\mathit{AC}$，$\mathit{BD}$相交于点$O$，$\mathit{DE}$平分$\angle \mathit{ADO}$交$\mathit{AC}$于点$E$，把$\mathit{\Delta ADE}$沿$\mathit{AD}$翻折，得到$\mathit{\Delta ADE}\text{'}$，点$F$是$\mathit{DE}$的中点，连接$\mathit{AF}$，$\mathit{BF}$，$E\text{'}F$．若$\mathit{AE}=\sqrt{2}$．则四边形$\mathit{ABFE}\text{'}$的面积是　　．