文章从理论上概述了外场作用下向列相液晶盒中出现的Bloch壁，使用负性液晶对两种垂面排列(VA)盒进行实验研究。两种液晶盒均使用垂面聚酰亚胺(PI)作为取向层，一种盒涂敷PI后使用了后工艺过程，另一种盒涂敷PI而没有后工艺过程。第一种VA盒在强场作用下出现壁，它事实上验证了涂敷PI后工艺过程的有效性。在外场作用下，第二种VA盒出现不同的不稳定现象。

We outline theoretically Bloch wall in nematic liquid crystal cell with the applied field. Two types of vertical alignment (VA) cell filled with negative liquid crystal are studied experimentally. Both types of liquid crystal cell have vertical alignment layer of polyimide (PI). One type of the cell uses the technological process after coating PI, the other does nothing after coating PI. The wall appears in the first type VA cell with the strong field, which in fact justifies the effect of the technological process after coating PI. Different instability phenomena appear in the second type VA cell with the applied field.