Flexible blackboard capable of preventing shielding of projection curtain

The utility model discloses a flexible blackboard capable of preventing a projection curtain from being shielded, which comprises a first blackboard block, a second blackboard block, a third blackboard block, a fourth blackboard block, a blackboard frame and a chain wheel and chain mechanism, the first blackboard block is arranged on the second blackboard block in a left-right sliding mode, the length of the fourth blackboard block in the horizontal direction is larger than that of the third blackboard block, the third blackboard block is arranged on the fourth blackboard block in a left-right sliding mode, the second blackboard block is arranged above the third blackboard block, and a gap exists between the second blackboard block and the third blackboard block. The two chain wheel and chain mechanisms are arranged on the left inner side and the right inner side of the blackboard frame respectively. The chain wheel rotates to drive the chain to move up and down so as to link the second blackboard block and t