Patent ID: 7974157
Filing Date: 2011-07-05
Classification: G01N,Y10T

Abstract:
1. An apparatus for indicating the passage of time, comprising: a substrate; a background layer formed on said substrate, said background layer being made from a first polymer binder, a base material and a background layer color rendering material, said base material being colorless and said background layer color rendering material displaying a background color such that said background layer displays said background color; a time passage indicating layer formed on said background layer, said time passage indicating layer covering a portion of said background layer, said time passage indicating layer being made from a solvent, a redox compound, a reducing agent and a second polymer binder wherein said second polymer binder bonds with said first polymer binder through physical or chemical bonding, said time passage indicating layer having an initial reduced state and a final oxidized state wherein said time passage indicating layer displays an initial color in said initial reduced state and a final color in said final oxidized state, said initial color is different from said final color and said final color is substantially the same as said background color, such that when in said final oxidized state, said time passage indicating layer becomes visually identifiable on said background layer to achieve an effect of said time passage indicating layer disappearing from said background layer; and at the beginning of the time passage to be indicated, all said redox compound in said time passage indicating layer is reduced to said initial reduced state, and later when said time passage indicating material is oxidized through contact with oxygen molecules, said time passage indicating layer gradually transforms from said initial reduced state to said final oxidized state, and the color of said time passage indicating layer changes from said initial color to said final color, when said final oxidized state is reached, said time passage indicating layer becomes visually unidentifiable on said background layer, indicating the end of the time passage to be indicated.