Integrating rod homogeneity as a function of cross-sectional shape

Abstract

We present preliminary results from an analysis of irradiance patterns from integrating rods. A new metric is proposed to provide a more rigorous characterization of homogeneity as compared to the current ANSI standard for illumination and brightness of rectangular integrating rods used in the projector and display industry. This new metric is used in a computational ray-trace analysis to compare the relative homogenizing efficiency of integrating rods as a function of the polygon order of the cross section. Our analysis is performed for an ideal surface-emitting disk in order to yield general insight into the workings of integrating rods for common light sources, and a for full radiometric source model based on measurements of a reflectorized 100W Hg arc lamp. Simulation results indicate that a high degree of homogenization can be achieved for integrating rods with cross sections of polygon order ≤10. These results refute the commonly held belief that only integrating rods with tileable cross-sectional shapes are effective homogenizers. These results are particularly significant for optical applications in the materials processing industry.

An enhanced method of obtaining uniform excitation radiation for fluorescence microscopy

“…Using this array, the uniformity across the FOV can be defined as the ratio of irradiance from the edge to the centre [5]. Such a definition has the drawback that it relies upon the polar symmetry of the source, but it simplifies the calculation, and is sufficient for these measurements since dimming at the edges of the FOV is ofmain concern4.…”

“…The micro-variation in uniformity in both cases is due to the electrical noise in the CCD and should not be considered as real features in the irradiance distributions. Lateral displacement along FOV (mm) Figure 8 Uniformity measurements with Zeiss Axioplan 2 microscope using a lOx objective ' Where micro-variation in uniformity in 2 dimensions is of concern, a 2 dimensional array may be used and various quantitative metrics for measuring uniformity may be employed [5]. Uniformity measurements with Zeiss Axioplan 2 microscope using a 40x objective Table 2 summarizes the results for this microscope using the edge-to-centre definition applied at a FOV diameter of 22mm.…”