NTT Research and Development 2006 Review of Activities

In environments containing precision devices, such as medical instruments, sensitive to electromagnetic-interference irradiated from electrical equipment, the influence of such interference on the operation of these instruments is a cause of great concern. Accordingly, techniques for suppressing this electromagnetic interference are vital. In recent times, with the advances in power-electronics technology, devices (such as fluorescent lights) incorporating inverter technology—which brings about energy saving by switching at relatively high frequency—are appearing in multiple markets. However, it is a problem that a considerable amount of electromagnetic interference is generated; thus, it is necessary to prevent the problem of electromagnetic compatibility (EMC) from occurring.

Although it is know that rapid-start-technology fluorescent-lighting fixtures utilized for conventional illumination produce relatively low electromagnetic noise and have little influence on sensitive instruments, they have the drawback of having no energy-saving effect. At the same time, inverter fluorescent lighting on the market causes a high level of electromagnetic noise, and significant transitional electromagnetic noise generated by switching. As a result, if conventional lighting and fixtures are replaced for the purpose of energy saving, there is the danger of generating EMC problems. In light of these circumstances, electromagnetic-interference and transitional-electromagnetic-noise suppression technologies have been developed, energy saving of 35% have been achieved, and lighting fixtures equipped with a high-frequency inverter electronic stabilizer—featuring fine fluorescent tubes utilizing non-mercury materials in line with RoHS regulations—have been developed (single-phase 100 V or 200 V).

These technologies have transferred to NTT East, NTT West, and NTT Communications, and commercialization expansion is being undertaken by NTT Advanced Technology (NTT-AT). At each NTT business organization as well, these technologies will be introduced during the planned renewal of the wall lighting for telecommunication equipment rooms. Furthermore, as regards suspended telecommunication-equipment lighting, introduction of these technologies at NTT group companies is being investigated. On top of that, NTT-AT is planning to market these technologies for lighting fixtures in environments where medical instruments susceptible to electromagnetic interference are located (such as hospitals).