Operating Principles
Induction lighting is based on technology that is fundamentally different from conventional gas sources
or incandescent lamps. Instead of electrodes used in gas discharge lamps or the glowing filament of incandescent,
light generation is by means of induction the transmission of energy by way of a magnetic field combined
with a gas discharge.
- Electrical Transformer Principle
The principle is the same as that of an electrical transformer (Figure 1.). An alternating current (Ip) in the primary coil induces a corresponding alternative magnetic field in the core and the surrounding space. This magnetic field in turn induces a current of the same frequency (Is) in the secondary coil. The higher the frequency of the alternating current, the higher the overall efficiency of the system, and the more compact the system can be.
Fig. 1. - Induced Current in the Lamp Bulb
The energy source in the induction lighting system equivalent to the primary coil of the transformer is the lamps induction coil, which is powered by the high-frequency electronics in the HF generator. The secondary coil is represented by the low-pressure gas and metal vapor inside the lamp bulb (Figure 2.). The induced current causes the acceleration of charged particles in the metal vapor. These particles collide, resulting in excitation and ionization of the metal vapor atoms, and raising the energy level of the free electrons from these atoms to a higher, unstable state. As these excited electrons fall back to their stable, lower-energy state, they emit ultraviolet radiation. This falls on the fluorescent coating inside the lamp bulb, causing light to be emitted.
Fig. 2. - Ultra-long lifetime
The ultra-long lifetime of the induction lighting system is attributable to two main factors: - There are no filaments or electrodes as in conventional lamps that are exposed to the effects of heat and high electrical potential, and as a result are subject to deterioration of performance and finally to failure.
- Because the induced magnetic field can easily pass through the glass wall of the lamp bulb, no throughput wires are needed as in incandescent or discharge lamps, where the glass/metal junction is another vulnerable failure area.
- Low Radiated Energy Levels
The high frequency power supply to the primary coil at 2.65 MHz well outside normal broadcast and communication radio bands ensures highly efficient energy transmission between the induction coil and the gas and metal vapor filling of the lamp bulb. Radiated energy levels close to an induction lighting system are no higher than from a distant radio transmitter, while the UV radiated power is no more than that of a standard fluorescent lamp of the same power.
