CalcuLens™ Vertex enables the LAS to make relevant distance measurements in optical assemblies. Utilizing a high numerical aperture (NA) objective, the application software records the vertical location of the cat's eye reflection from upper and lower lens surfaces. Distance between surfaces is derived from the different lens surface heights using reverse ray-trace. Output is the highlighted surface-to-surface error column below. This tells the LAS user the magnitude of error in center thickness (CT) and air gap relative to the design specification, as input by the user in CT/airgap (4th column). Thus, Vertex measurement verifies actual air gaps and lens thicknesses, accurate to within ±2.5 μm. Precision of the Z-axis encoder with temperature compensation software provides micron level repeatability on thickness measurements.
The standard Vertex objective has a working distance (WD) of 30 mm, but a long-snout objective is available for Vertex measurement in deep housings > 200mm. 40mm and 50mm WD objectives are also available upon request. When Vertex is equipped with the 50mm WD objective, it can measure air gaps and lens thicknesses to stack depths up to 50mm. For assemblies larger than 50mm, measurements must be made piece-wise as the lenses are assembled because measurements can only be made within 50mm of the objective. This works well, measuring from lens to lens during assembly of larger stacks. Another option is to flip a lens assembly, consecutively measuring the top 50mm and then the bottom 50mm. In this way it is possible to measure up to a 100mm lens stack using LAS with Vertex and a 50mm WD objective.
Overall, CalcuLens™ Vertex provides a quick, accurate, and low-cost means of distance measurement for lenses or assembles measured on the LAS.