| 摘要 |
PROBLEM TO BE SOLVED: To accurately judge dewing by dividing the heating and cooling processes of a detection member into two steps and reducing the absolute value of a supply current value with the advance of the steps. SOLUTION: When the heating and cooling processes Ph, Pc of a module are divided into first and second steps, the absolute values I2 , I1 of the supply currents of the respective steps become I2 >I1 and, therefore, in both of the processes Ph, Pc, the temp. of a detection member (plate) rises or falls suddenly in the first step and rises or falls slowly in the second step. The ratioγ1 /γ2 of the temp. change gradientsγ1 ,γ2 in both steps almost becomes a predetermined value (1) when there is no dewing and the temp. change gradientγ2 becomes small when dewing is generated and the ratioγ1 /γ2 exceeds the predetermined value. Therefore, when these states are observed, the possibility of dewing can be detected. At this time, if a large current I2 is supplied in the first step of the process Pc to cool the rnodule to a temp. region generating dewing rapidly and a small current I1 is supplied in the next second step to extend the timeΔt by dewing the change of the ratioγ1 /γ2 can be certainly grasped. |
