Reading dry chemical arrays through the substrate

Abstract

A method of interrogating an addressable array unit having a transparent substrate with a back surface, and an array with a plurality of different chemical features on a front surface. The method may include illuminating the features while the array is dry, with an interrogating light which is directed through the substrate from the back surface and onto the chemical features on the front surface. The light emitted from respective features in response to the interrogating light may be detected, which detected light has passed from the front surface, through the substrate and out the back surface. In one arrangement the light is emitted from locations of the features which are spaced from the front surface a distance of less than one-eighth of the wavelength of the illuminating light in a gas or a vacuum which is in contact with the dry array. Other methods and a package containing an addressable array are also provided.

1 - 15 . (canceled)  
   
   
       16 . A package comprising: 
 an addressable array unit having a transparent substrate with a back surface, and an array with a plurality of different chemical features on a front surface, the chemical features having a thickness of less than 100 nm; and    instructions to:    (i) interrogate the array with an interrogating light which is directed through the substrate from the back surface and onto the chemical features on the front surface; and    (ii) detect light emitted from respective features in response to the interrogating light, which detected light has passed from the front surface, through the substrate and out the back surface.    
   
   
       17 . A package according to  claim 16  wherein the features have a thickness of less than 50 nm.  
   
   
       18 . A package according to  claim 16  wherein the features have a thickness of less than 10 nm.  
   
   
       19 . (canceled)  
   
   
       20 . A method for use with an interrogating an addressable array unit having a transparent substrate with a back surface, and an array with a plurality of different chemical features on a front surface, the method comprising: 
 (a) machine reading an identifier associated with the array unit;    (b) based on the read identifier, retrieving by a processor an instruction that the array should be interrogated and read through the substrate from the back surface.    
   
   
       21 . A method according to  claim 20  wherein the identifier is on the array substrate or a housing carrying the array substrate.  
   
   
       22 . A method according to  claim 20  wherein the instruction is retrieved from the read identifier.  
   
   
       23 . A method according to  claim 20  wherein the instruction is retrieved from a memory using data from the read identifier.  
   
   
       24 . A method according to  claim 20  additionally comprising checking that the array is oriented within an array reader such that the array can be interrogated and read by the reader through the substrate from the back surface.