**5. Conclusion**

It has been presented that the space charge distribution can be clarified in thin polyimide film using LIMM method from relatively low field of 2.5 kV/mm up to 125 kV/mm, which is close to breakdown field. The electric field enhancement due to space charge accumulation is shown to be 1.4 times at 25 kV/mm under room temperature condition. To design much reliable structure against space charge accumulation in polyimide and encapsulation material, its distributions are needed to be clarified by the further study.
