Abstract
In recent years, along with the development and diffusion of light sources for illumination and display using light-emitting diodes (LEDs) or electro-luminescence (EL), how to evaluate the performance of phosphors used as materials in these sources has become a big issue. Quantum efficiency is a particularly important property to be evaluated, and in a previous work we proposed a method to measure the quantum efficiency of phosphor powder samples using a system comprising the integrating sphere. In this system, the polychromator, which features an incident optical system with an integrating sphere to measure excitation and emission, is calibrated with a beam of white light with a known relative spectral distribution. The beam of white light is calibrated with a spectral irradiance standard lamp traceable to the Japan Calibration Service System (JCSS) meeting the requirements of the Measurement Law, and therefore, it can be said that the spectral responsivity of the system is traceable to JCSS. Since requests to measure not only the powder but also the solution samples have recently been increasing, we have developed a system with an integrating hemisphere that uses the measurement techniques described above and can measure both powder and solution samples with ease. In this work, we examined the measurement method for phosphor solution samples using the developed system and determined the system performance through evaluations of standard phosphor materials.
