OPERATION INPUT MECHANISM, INPUT KEY PIECE, AND KEY BASE

摘要

There is disclosed an operation input mechanism which prevents erroneous arrangement of an input key piece. The operation input mechanism includes: a plurality of input key pieces, each having a pressing unit and a flange unit arranged at the periphery of the pressing unit; and a key base having a support unit for supporting the input key pieces. The flange unit has an identification cut-off portion for identifying the type of the input key piece and a visually distinguishable identification convex/concave pattern corresponding to the identification cut-off portion. The support unit has an identification protrusion to be brought into abutment with the identification cut-off portion. The pressing unit may have a visually distinguishable operation input printed pattern corresponding to the identification convex/concave pattern.