Patent ID: 7691458

Claim:
An apparatus, comprising: a carrier substrate having a visible surface and a heat generating component electrically coupled to the carrier substrate; a thermochromatic material having an activation temperature, disposed adjacent to the carrier substrate, wherein the thermochromatic material produces a visual change of the visible surface when the activation temperature of the thermochromatic material is reached; and a solder mask layer, wherein the solder mask layer is transparent and overlaying the thermochromatic material adjacent to the carrier substrate, wherein the carrier substrate coupled to the heat generating component has normal operating temperatures when the carrier substrate and heat generating component operate normally, and wherein the thermochromatic material is selected to have its activation temperature above the normal operating temperatures of the carrier substrate coupled to the heat generating component; wherein said thermochromatic material comprises a material selected from the group consisting of leucodye and N-isopropylacrylamide to change from a first color and a second color.