Stimulus indication employing polymer gels

Abstract

Techniques and devices are presented for communicating exposure to a potentially harmful stimulus. The devices include a stimulus sensitive gel which changes volume in response to exposure to the stimulus and thereby presents a contrast in color that serves as a visual indicator that exposure to the stimulus has occurred.

What is claimed is: 
     
         1 . A device for communicating exposure to a stimulus, the device comprising:
 a stimulus sensitive gel;   a compartment containing the stimulus sensitive gel; and   an indicator spot positioned in one end of the compartment,   wherein the stimulus sensitive gel expands in size in response to exposure to the stimulus.   
     
     
         2 . The device of  claim 1 , wherein the indicator spot is covered after the stimulus sensitive gel has been exposed to the stimulus. 
     
     
         3 . The device of  claim 1 , wherein the indicator spot is covered when the stimulus sensitive gel has been exposed to the stimulus for a predetermined period of time. 
     
     
         4 . The device of  claim 1 , wherein the stimulus includes temperature. 
     
     
         5 . The device of  claim 1 , wherein the stimulus sensitive gel and the indicator spot each have different colors that can be distinguishable from each other. 
     
     
         6 . The device of  claim 5 , wherein the indicator spot is a symbol. 
     
     
         7 . The device of  claim 1 , wherein the stimulus sensitive gel and the indicator spot have the same color. 
     
     
         8 . The device of  claim 7 , wherein the indicator spot is a symbol. 
     
     
         9 . The device of  claim 1 , further comprising:
 an attachment point for securing a portion of the gel to the compartment,   wherein when the gel changes volume, it remains connected to the attachment point.   
     
     
         10 . A stimulus-indicating device comprising:
 a stimulus sensitive gel;   a first compartment;   a second compartment connected to the first compartment via a neck portion,   wherein the stimulus sensitive gel can be contained in either said first compartment or said second compartment;   a display portion positioned above either the first or second compartments through which a visual change can be seen in an indicator spot when the stimulus sensitive gel changes volume in reaction to a predetermined stimulus; and   an upper layer and a lower layer within the first and/or second compartments,   wherein the stimulus sensitive gel is permanently attached to either the upper layer or the lower layer or both.   
     
     
         11 . The device of  claim 10 , wherein the indicator spot is a symbol. 
     
     
         12 . A stimulus-indicating device comprising:
 a stimulus sensitive gel;   a first compartment;   a second compartment connected to the first compartment via a neck portion,   wherein the stimulus sensitive gel can be contained in either said first compartment or said second compartment; and   a display portion positioned above either the first or second compartments through which a visual change can be seen in an indicator spot when the stimulus sensitive gel changes volume in reaction to a predetermined stimulus;   wherein the stimulus sensitive gel expands in size in response to exposure to the predetermined stimulus.   
     
     
         13 . The device of  claim 12 , wherein the indicator spot is a symbol. 
     
     
         14 . A stimulus-indicating device comprising:
 a stimulus sensitive gel;   a first compartment;   a second compartment connected to the first compartment via a neck portion,   wherein the stimulus sensitive gel can be contained in either said first compartment or said second compartment; and   a display portion positioned above either the first or second compartments through which a visual change can be seen in an indicator spot when the stimulus sensitive gel changes volume in reaction to a predetermined stimulus;   wherein the stimulus sensitive gel is held in place in its expanded form in both compartments by the neck portion after it expands in size in response to exposure to the predetermined stimulus.   
     
     
         15 . A dual stimulus-indicating device comprising:
 a first stimulus-indicating portion containing a first stimulus sensitive gel that is sensitive to a first predetermined stimulus; and   a second stimulus-indicating portion containing a second stimulus sensitive gel that is sensitive to a second predetermined stimulus.   
     
     
         16 . The stimulus-indicating device of  claim 15 , wherein each of the first and second stimulus sensitive gels contract in size in response to exposure to the respective predetermined stimuli. 
     
     
         17 . The stimulus-indicating device of  claim 15 , wherein an indicator spot becomes visible when each of the stimulus sensitive gels has been exposed to the respective predetermined stimulus. 
     
     
         18 . The stimulus-indicating device of  claim 15 , wherein an indicator spot becomes visible when each of the stimulus sensitive gels has been exposed to the respective predetermined stimuli for a predetermined period of time. 
     
     
         19 . The stimulus-indicating device of  claim 15 , wherein each stimulus sensitive gel and its respective indicator spot each have different colors that can be distinguishable from each other. 
     
     
         20 . The stimulus-indicating device of  claim 15 , wherein the stimulus includes temperature.