| 摘要 |
PURPOSE:To provide an illumination device capable of preventing the occurrence of a spot due to mercury cohesion on the lower surface side of a bulb when a T8 type fluorescent lamp is fitted to an open type lighting apparatus, and of checking luminous efficacy deterioration due to temperature rise when attached to a closed type lighting apparatus. CONSTITUTION:An illumination device features that a vent hole 11 is formed on a position oposite to a bulb end part on the ceiling surface 8 of a lighting apparatus 1 in an illumination device in which a T8 type fluorescent lamp 4 is fitted to perform high frequency lighting in the lighting apparatus of both open and closed types. Forming the vent hole facing the bulb end part on the ceiling surface of the lighting apparatus, flows air via the vent hole, and cools the bulb end part by an air flow to form the coolest part on the bulb end part. |
