Optical systems and methods for biological analysis

Abstract

An instrument for processing and/or measuring a biological process contains an excitation source, a sample holder, an optical sensor, an excitation optical system, and an emission optical system. The sample holder is configured to receive a plurality of biological samples. The optical sensor is configured to receive an emission from the biological samples. The excitation optical system is disposed along an excitation optical path and is configured to direct the electromagnetic radiation from the excitation source to the biological samples. The emission optical system is disposed along an emission optical path and is configured to direct electromagnetic emissions from the biological samples to the optical sensor. The instrument further contains a plurality of filter assemblies configured to be interchangeably located along at least one of the optical paths. The plurality of filter components includes a first filter assembly characterized by a first optical power and a first filter having a first filter function, the first filter function characterized by at least one of a first low-pass wavelength or a first high-pass wavelength. The second filter assembly is characterized by a second optical power and a second filter having a second filter function, the second filter function comprising at least one of a second low-pass wavelength that is different than the first low-pass wavelength or a second high-pass wavelength that is different than the first high-pass wavelength.

What is claimed is: 
     
         1 . An instrument for biological analysis, comprising:
 an excitation source producing electromagnetic radiation;   a sample holder configured to receive a plurality of biological samples;   an optical sensor configured to receive an emission from the biological samples;   an excitation optical system configured to direct electromagnetic radiation from the excitation source to the biological samples;   an emission optical system disposed along an emission optical path and configured to form an image of the biological samples at an image plane located on or proximal to the optical sensor;   a plurality of filters having different transmission wavelength bands, the filters being interchangeably located along the emission optical path;   wherein the image plane of the biological samples have the same location along the emission optical path when any one of the filters is located along the emission optical path.   
     
     
         2 . The instrument of  claim 1 , wherein the image plane is located within 100 micrometers of a surface of the optical sensor. 
     
     
         3 . The instrument of  claim 1 , further comprising a sample array disposed within the sample holder, the sample array comprising the plurality of biological samples. 
     
     
         4 . The instrument of  claim 3 , wherein the image of the biological samples comprises a plurality of spots comprising emissions from corresponding ones of biological samples. 
     
     
         5 . The instrument of  claim 1 , wherein at least one filter of the plurality of filters comprises a singlet lens such that the at least one filter has a non-zero optical power for electromagnetic radiation transmitted through the at least one filter. 
     
     
         6 . The instrument of  claim 1 , wherein the plurality of filters comprises:
 a first filter comprising of a low-pass or high-pass wavelength filter having no optical power.   
     
     
         7 . The instrument of  claim 1 , further comprising a filter assembly configured to selectively position a filter of the plurality of filters into the emission optical path. 
     
     
         8 . An instrument for biological analysis, comprising:
 an excitation source producing electromagnetic radiation;   a sample holder configured to receive a plurality of biological samples, the sample holder extending over a rectangular area having a first aspect ratio of a first value;   an optical sensor configured to receive an emission from the biological samples;   an excitation optical system configured to direct the electromagnetic radiation from the excitation source to the biological samples;   an emission optical system configured to direct electromagnetic emissions from at least some of the biological samples to the optical sensor;   a rectangular emission filter disposed along an optical path between the sample holder and the optical sensor, the rectangular emission filter having a second aspect ratio of a second value;   wherein the first value is within twenty percent of the second value.   
     
     
         9 . The instrument of  claim 8 , wherein first value is within five percent of the second value. 
     
     
         10 . The instrument of  claim 8 , wherein the first value is the same as the second value. 
     
     
         11 . The instrument of  claim 8 , further comprising a second rectangular emission filter having a third aspect ratio of a third value, wherein the first value is within twenty percent of the third value. 
     
     
         12 . The instrument of  claim 8 , wherein the rectangular emission filter comprises a singlet lens such that the rectangular emission filter has a non-zero optical power for electromagnetic radiation transmitted through the filter. 
     
     
         13 . The instrument of  claim 8 , further comprising a second rectangular emission filter. 
     
     
         14 . The instrument of  claim 13 , further comprising a filter assembly configured to selectively position the rectangular emission filter or second rectangular emission filter into the emission optical path. 
     
     
         15 . An instrument for biological analysis, comprising:
 an excitation source producing electromagnetic radiation;   a sample holder configured to receive a plurality of biological samples;   an optical sensor configured to receive an emission from the biological samples;   an excitation optical system disposed along an excitation optical path and configured to direct the electromagnetic radiation from the excitation source to the biological samples;   an emission optical system disposed along an emission optical path and configured to direct electromagnetic emissions from the biological samples to the optical sensor;   wherein the excitation source comprises an LED having a spectral profile with a maximum value equal to a maximum intensity or maximum optical output power at a wavelength that is less than 600 nanometers and by an intensity or an optical output power that is less than 30 percent the maximum value at a wavelength of 670 nanometers.   
     
     
         16 . The instrument of  claim 15 , wherein the excitation source comprises an LED having a spectral profile with a maximum intensity or optical output power at a wavelength that is less than 550 nanometers and an intensity or optical output power that is less than 30 percent the maximum value at a wavelength of 650 nanometers. 
     
     
         17 . The instrument of  claim 15 , further comprising a plurality of filter components, the plurality of filter components comprising:
 a first filter component having no optical power, the first filter component comprising of a first filter characterized by at least one of (a) a first low-pass wavelength or (b) a first high-pass wavelength.   
     
     
         18 . The instrument of  claim 17 , further comprising a filter assembly configured to selectively position a filter component of the plurality of filter components into the emission optical path. 
     
     
         19 . The instrument of  claim 15 , further comprising a plurality of filters wherein at least one filter of the plurality of filters comprises a singlet lens such that the at least one filter has a non-zero optical power for electromagnetic radiation transmitted through the at least one filter. 
     
     
         20 . The instrument of  claim 17 , wherein the sample holder has a first aspect ratio having a first value; and
 the plurality of filter components comprises a rectangular emission filter having a second aspect ratio of a second value, wherein the first value is within twenty percent of the value second value.