| 摘要 |
PURPOSE:To improve characteristics to a temperature change of a key board, and to enhance the commonalty of a back board by forming the projecting sections of the periphery of the back board at least four points or more and forming a clearance between the key board and the back board. CONSTITUTION:The clearance is constituted between the back board 28 and the key board 13 when both are combined by forming six projections 30 for air vent in the peripheral section of the back board 28 and one at the central section on the key board 13 side. According to such constitution, when the key of the key board 13 is pressed and when heat is applied and the temperature of a key section rises, air is vented from the sealed chamber of the key section by the air vent hole of key board 13 itself, and air is vented from the clearance between the key board 13 and the back board 28. When the press of the key is stopped, on the other hand, air intrudes into the sealed chamber of the key section. Accordingly, there is no necessity for constituting the back boards different at each key board, and the heater can be installed to the key boards 13 of the same external form by the same back board 28. |
