Low-Cost IR Visualizer Based on a Rotating Phosphor Screen for Accurate Beam Analysis

Abstract

We present a low-cost IR beam analysis tool based on a rotating phosphor screen. The infrared light incident on the IR-sensitive screen was converted to visible light by the IR-responsive phosphor that operated by light charging and IR-induced luminescence. Through comparative experiments, the conventional IR viewing card, based on the same kind of phosphor, was found to exhibit a short luminescence time because the excited fluorescent molecules are depleted locally at the beam spot. This effect hinders accurate estimation on the spatial characteristic of the IR beam and consequently limits the capability of the IR viewing card in beam inspection. Our IR visualizer alleviates this effect by rotating the IR-sensitive screen in a high speed so that the luminescence time was effectively prolonged to allow a longer measurement time for the IR beam. Our scheme provides a simple and economic means of IR beam inspections, especially useful for the wavelength band above 1,000 nm where the solid-state image sensors are hardly available in low cost.