An image capturing apparatus includes a light emitting unit and an image sensor having a plurality of pixels are disposed in a matrix. The heat spreading member extends larger than the predetermined surface. The exemplary locking mechanism also includes a second member positionable between first and second configurations, wherein the first configuration extends the second member through the first member in the second configuration to secure the first member. The method further includes comparing the inlet humidity value with the outlet humidity value to determine the amount of moisture that the dehumidifier is removing for the air. 0\ue89e\ue89emm\u2264A+B2\u226427. In certain embodiments, the phosphonium compound is a tetraaryl phosphonium salt.