Method and apparatus for detecting target chemicals with transparent indicator tape

Abstract

Transparent indicator tape is used for the detection of airborne chemicals in a suspect environment. In various embodiments, the indicator tape is affixed to a window or lens wherein one or more colorimetric indicators clad to the tape are exposed to the environment while humans or detection devices on the other side of the window or lens are not necessarily subjected to the suspect environment. In various embodiments the colorimetric indicator is sensitive to chemical warfare agents. Airborne chemicals including chemical warfare agents may detected by visual review or autonomous measurement of sensor color changes when in the presence of a target chemical. In various embodiments, the an indicator spot is split into sensitive and insensitive regions such that colorimetric changes may be more readily identified against a visually changing background.

I claim: 
     
         1 . A system for the passive detection of target airborne chemicals in an environment,
 comprising:   at least one colorimetric indicator which changes color when exposed to at least one target airborne chemical;   a transparent polymer substrate,
 wherein the at least one colorimetric indicator is clad to the transparent polymer substrate, 
 wherein the transparent polymer substrate is affixed to an environment facing surface of a transparent window or lens; 
   an optical detector located adjacent to a non-environment facing surface of the transparent window or lens;   wherein the transparent polymer substrate is positioned between the optical detector and the environment such that a line of sight from the environment and the optical detector passes through the transparent polymer substrate;   whereby when exposed to a target airborne chemical the corresponding colorimetric indicator clad to the transparent polymer substrate changes color, indicating presence of the at least one target airborne chemical.   
     
     
         2 . The system of  claim 1  wherein the at least one target airborne chemical is a chemical warfare agent. 
     
     
         3 . The system of  claim 1  also comprising an opto-electronic reader capable of discerning color changes of the at least one corresponding colorimetric indicator coating. 
     
     
         4 . The system of  claim 1  wherein the transparent polymer substrate is transparent tape. 
     
     
         5 . The system of  claim 1  wherein the window is a vehicle window. 
     
     
         6 . The system of  claim 1  wherein the lens is a camera lens. 
     
     
         7 . The system of  claim 1  wherein the window is a window of a fixed structure. 
     
     
         8 . The system of  claim 5  wherein the vehicle is an unmanned vehicle. 
     
     
         9 . The system of  claim 1  wherein the at least one colorimetric indicator covers at least a first portion of a contiguous regular shape and wherein at least a second portion of the contiguous regular shape is either covered by a transparent material blocking exposure to the suspect environment or is not covered by the at least one colorimetric indicator. 
     
     
         10 . A method for passive detection of target airborne chemicals comprising:
 exposing to a suspect environment at least one corresponding colorimetric indicator which changes color when in contact with at least one target airborne chemical in the suspect environment;   wherein the at least one corresponding colorimetric indicator is immobilized into a transparent polymer substrate affixed to an environment facing surface of a transparent window or lens;   discerning color changes of the at least one corresponding colorimetric indicator;   whereby the color changes of the at least one corresponding colorimetric indicator indicate the presence of the at least one target airborne chemical in the suspect environment.   
     
     
         11 . The method of  claim 10  wherein the at least one target airborne chemical is a chemical warfare agent. 
     
     
         12 . The method of  claim 10  wherein the transparent polymer substrate is transparent tape. 
     
     
         13 . The method of  claim 10  wherein the window is a vehicle window. 
     
     
         14 . The method of  claim 10  wherein the lens is a camera lens. 
     
     
         15 . The method of  claim 10  wherein the at least one colorimetric indicator covers at least a first portion of a contiguous regular shape and wherein at least a second portion of the contiguous regular shape is either covered by a transparent material blocking exposure to the suspect environment or is not covered by the at least one colorimetric indicator. 
     
     
         16 . A transparent chemical indicator tape comprising:
 at least one colorimetric indicator which changes color when exposed to at least one target airborne chemical;   a transparent polymer substrate,
 wherein the at least one colorimetric indicator is clad to the transparent polymer substrate, 
 wherein the transparent polymer substrate is affixable to an environment facing surface of a transparent window or lens, 
 wherein the transparent polymer substrate is a transparent indicator tape; 
   wherein the transparent tape may be positioned between an optical detector and the environment such that a line of sight from the environment and the optical detector passes through the transparent indicator tape;   whereby when exposed to the at least one target airborne chemical the corresponding colorimetric indicator clad to the transparent polymer substrate changes color, indicating presence of the at least one target airborne chemical.   
     
     
         17 . The transparent indicator tape of  claim 16  wherein the at least one target airborne chemical is a chemical warfare agent. 
     
     
         18 . The transparent indicator tape of  claim 16  wherein the lens is a camera lens. 
     
     
         19 . The transparent indicator tape of  claim 16  wherein the window is a vehicle window. 
     
     
         20 . The transparent indicator tape of  claim 16  wherein the at least one colorimetric indicator covers at least a first portion of a contiguous regular shape and wherein at least a second portion of the contiguous regular shape is either covered by a transparent material blocking exposure to the suspect environment or is not covered by the at least one colorimetric indicator.