CRISP Autofocus System
About the CRISP System
The CRISP system is designed to maintain focus over time i.e. compensate for thermal & other factors that may cause the sample to drift out of focus. It also can be used to maintain a given focal point while scanning the sample in XY. If you are looking to find the optimal focal point while scanning through the sample in Z please see our video autofocus system.
CRISP will not work with index matching mounting media. This is how most prepared slides are made. There is no interface with a refractive change near the sample to reflect the light. CRISP relies on reflected light from the sample to detect focus position. Often the reflected light comes from small refractive index discontinuities at sample surfaces. The amount of light reflected at a dielectric interface is given by: R=(n1-n2)^2/(n1+n2)^2
Where n1 and n2 are the reflective indexes of the adjoining dielectric materials. There must be a difference between the refractive indexes in order for CRISP to work.