Thermochromic Level Indicator

Abstract

A thermochromic ink or print varnish is formulated and printed to form a level indicator.

1 . A housing comprising
 a wall presenting an interior space capable of retaining matter at a first level within the wall;   means for permitting the matter to exit from within the wall or enter into the wall such that the matter assumes a second level;   the wall supporting a level indicator,   the level indicator being formed of thermochromic ink,   the thermochromic ink having a color transition temperature capable of acting as a level indicator by sensing temperature of the matter retained within the wall in an intended environment of use.   
     
     
         2 . The housing of  claim 1 , wherein the matter is a beverage and the wall is at least part of a beverage container. 
     
     
         3 . The housing of  claim 1 , wherein the level indicator is printed as an indicia representing an image of an object. 
     
     
         4 . The housing of  claim 3  where the image is a glass. 
     
     
         5 . The housing of  claim 3  where the image is a thermometer. 
     
     
         6 . The housing of  claim 3  where the image is a rainbow. 
     
     
         7 . The housing of  claim 3  where the image is a vertically oriented line. 
     
     
         8 . The housing of  claim 1  wherein the thermochromic ink included scented microcapsules. 
     
     
         9 . A method of sensing a liquid level using the housing of  claim 1 , comprising:
 filling the housing with the matter to the first level;   chilling the housing to a temperature exceeding a color transition temperature of the thermochromic ink;   removing matter from the housing to arrive at the second level in an environment such that the environmental temperature warms a portion of the thermochromic ink above the second level to a level above the color transition temperature; and   observing the color change to assess an approximate level of the matter within the housing.