Patent attributes
A humidity indicator includes a first film (F1) covering a surface of a humidity-determining plate (B), and a second film (F2) covering a back of the humidity-determining plate (B). A flat air layer (Au) is formed at least between the first film (F1) and the surface of the humidity-determining plate (B), so that the entire surfaces of humidity-determining faces (M1 to M4), to which cobalt chloride (CO) is exposed, face to the air layer (Au), and a plurality of small holes (H) are formed at distances from one another in the first film (F1) to permit the direct communication of the air layer (Au) with the atmosphere. Therefore, even if an operator picks, with his or her hand, a humidity indicator for determining humidity by the discoloration of cobalt chloride, the cobalt chloride on a humidity-determining face is prevented effectively from adhering to the operator's hand and thus, entering into his or her body. In addition, even if fine dust is generated from a base paper sheet of the humidity indicator, it is hard for the dust to be diffused to the surroundings, thereby effectively preventing the influence of the dust to electronic parts.
