The following application was filed in 2013 and directed to lighting a sample with both direct and indirect light.
It seems that companies have been providing this since at least 2003. For example, US 7,596,251 to Nexus Biosystems -
"Off-axis lighting tends to create subtle shadows on small objects in the target area viewed by the image device 142. The shadows caused by off-axis lighting make the objects much more visible than simple direct lighting of the sample from below. The controller 190 can control the imaging device 142 to capture two images of the sample. The imaging device 142 captures one image with the illumination module 152 lighting the sample with the first xenon flash tube. The imaging device 142 captures a second image with the illumination module 152 lighting the sample with the second xenon flash tube. The controller 190 can then combine the image data and perform an analysis based on the combined data. The processor 170 can perform an accurate analysis of small objects in the sample using the combined data."
The Application in question is:
Publication number US 20140038206 Application number US 13/951,063 Publication date Feb 6, 2014 Filing date July 25, 2013
A representative claim -
An illumination source;
A sample holder configured to receive light from the illumination source to provide both trans and epi illumination to the sample in the sample holder, wherein the illumination source is positioned to illuminate substantially only one side of the sample holder.
Can anyone find better prior art than Nexus Biosystems predating July 25, 2013?