This paper researches the possibility of reducing CO₂ emissions within the urban infrastructure by replacing current high pressure mercury fluorescent lamp streetlights with LED streetlights. To facilitate this transition, this paper investigates the standardization of new street light units in Kita ward, Tokyo. Based on this transition, the study calculates the future effects of LED lighting, focusing on the economic benefits for Kita ward. A discussion of the social and economic benefits of LED lighting concludes the paper.

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The present electrodeless lamp system operates at 135 kHz and has a higher efficiency and output than the high pressure mercury lamp system, which is currently very popular in the market. However, in terms of the starting performance, the 135 kHz electrodeless lamp system needs a much higher voltage than its 13.56 MHz predecessor. With regard to the ignition for inductively coupled electrodeless lamps, it has been reported that there are theoretically two types of ignition: E-discharge and H-discharge. E-discharge uses capacitively coupled plasma and is utilized for plasma processing as the dielectric barrier discharge lamp (DBD lamp) or for back lighting as the external electrode fluorescent lamp (EEFL). This lamp plasma is sustained by the electric field passing through the glass wall from the power source. H-discharge uses inductively coupled plasma and is utilized for lighting. This lamp plasma is sustained by the electromotive force generated by the alternating magnetic field. The ignition of this lamp is defined as the time when the H-discharge occurs, as this is an inductively coupled electrodeless lamp. The starting voltage of the 135 kHz electrodeless lamp system is higher than 1 kV, so it is expected to reduce the starting voltage because of the insulation. Observation of the starting state of the 135 kHz electrodeless lamp system showed that discharge occurred at a relative low coil voltage. It was also shown that the starting voltage could be decreased when the turns of the coil wire are decreased under the condition that the product of the wire turns and the frequency and current are both kept constant.

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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.

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