| 摘要 |
PURPOSE:To increase emission efficiency by arranging two induction coils which generate high-frequency electro-magnetic field of the same axis but opposite direction in the center of a bulb and in the outside of the bulb. CONSTITUTION:The inner wall of a bulb 11 is coated with a phosphor 13, and metal vapor and inactive gas are sealed in the bulb 11. A radio frequency oscillator 14 consists of an oscillator main body 15, an inner induction coil wound on an insulating core rod, and an outer induction coil 19 wound on the outer wall of the bulb 11. Magnetic fields generated by coils 17 and 19 are set to have an opposite direction each other. Synthetic magnetic field of each magnetic field generated by coils 17 and 19 is negated in the inside of the coil 17 and super posed in the outside of the coil 17 and in the inside of the coil 19 by the action in the same direction of each magnetic field. Since metal vapor and inactive gas exist in a space between the outer side of the coil 17 and the inner side of the coil 19, luminous flux is increased by strengthening the magnetic field of the space. Therefore, efficiency is increased. |
