| abstract |
In the heat-sensitive indicator herein disclosed, a colored heat-fusible substance 3 is accommodated in an inner hollow portion of a projection 1 which is formed from a film collapsible by application of an external pressure such as a finger-pressure. The opening of the hollow portion is sealed with a thin cover 9 collapsible through the application of the foregoing pressure. An An absorber 7 in which the colored heat-fusible substance 3 in the molten state can permeate is arranged outside the thin cover 9 of the hollow portion. The colored heat-fusible substance 3 is supported by a carrier 5 and accommodated in the interior of the hollow portion of the projection 1. A space in which the carrier is dropped when the thin cover 9 is broken through the application of a pressure is formed, behind the thin cover 9, by a hollow ring 11. The carrier 5 is positioned within the hollow ring 11, which forms the space outside the opening of the hollow portion and behind the thin cover 9 for the opening, and on the absorber 7. The carrier 5 serves to control the rate of permeation of the colored heat-fusible substance into the absorber and accordingly, stable permeation thereof into the absorber 7 can be ensured. |