Sensor with holographic multiplexed image display

Abstract

A holographic sensor comprising a thin film polymer matrix that undergoes a change in response to a substance to be sensed, the matrix containing within its volume a set of two or more holographic recordings, each recording providing a holographic image when the sensor is illuminated, wherein the presence or appearance of each image is visible to the eye as a function of the response of the sensor to the substance to be sensed. The images provide the dynamic range of the sensor. Such a sensor can be used to provide a visible image that changes or appears to the eye in response to an analyte.

1 . A holographic sensor which comprises a thin film polymer matrix that undergoes a change in response to a substance to be sensed, the matrix containing within its volume a set of two or more holographic recordings, each recording providing a holographic image when the sensor is illuminated, wherein the presence or appearance of each image is visible to the eye as a function of the response of the sensor to the substance to be sensed, and the images provide the dynamic range of the sensor.  
     
     
         2 . A sensor according to  claim 1 , wherein each image has a unique location in the visible or invisible spectrum.  
     
     
         3 . A sensor according to  claim 1  or  claim 2 , wherein each image is pictorial, numerical and/or alphabetical.  
     
     
         4 . A sensor according to any preceding claim, which provides a visible image in the presence of the substance.  
     
     
         5 . A sensor according to  claim 4 , wherein the visible image is representative of the substance or a scenario in which the substance is found or the sensor is used.  
     
     
         6 . A sensor according to  claim 5 , wherein the visible image is numerical.  
     
     
         7 . A sensor according to  claim 5 , wherein the visible image is alphabetical and provides a message corresponding to the substance or a scenario in which the substance is found or the sensor is used.  
     
     
         8 . A sensor according to  claim 5 , wherein the visible image has a location, in the space of the image, corresponding to or representative of the substance or a scenario in which the substance is found or the sensor is used.  
     
     
         9 . A sensor according to any of  claims 4  to  8 , wherein the visible image is calibrated with respect to the quantity of the substance.  
     
     
         10 . A sensor according to any of  claims 4  to  9 , which provides another visible image in the absence of the substance.  
     
     
         11 . A sensor according to any preceding claim, which additionally comprises a visible scale.  
     
     
         12 . A sensor according to  claim 11 , wherein the scale is invariant with respect to the concentration of the substance.  
     
     
         13 . A sensor according to any preceding claim, which provides multiple images within one film.  
     
     
         14 . A sensor according to any preceding claim, which provides at least three images.  
     
     
         15 . A sensor according to any preceding claim, which comprises a plurality of films each providing its own dynamic range within the dynamic range of the sensor.  
     
     
         16 . A sensor according to any preceding claim, which comprises a plurality of films each responding to a different substance.  
     
     
         17 . A sensor according to any preceding claim, which additionally comprises a colour transmission filter.  
     
     
         18 . A sensor according to any preceding claim, where the image is formed from a set of visible pixels, the pattern of pixels being indicative or representative of the substance or a scenario in which the substance is found or the sensor is used.  
     
     
         19 . Apparatus comprising a sensor according to any preceding claim and an illumination source.