1. Field of the Invention
The present invention relates to fluorescent fixtures having light diffusers and, more particularly, such fixtures for use in moving vehicles which also include air diffusers.
2. Description of the Related Art
Many existing public vehicles have antiquated fluorescent fixtures. These fixtures were installed many years ago when the vehicles were new and often little attention was paid at that time to providing fixtures which had adequate light diffusers. Also, for such fixtures, a requirement exists for providing air diffusion air temperature mixing, and the limiting of downward velocities upon vehicle passengers. With additional requirements for allowing easy maintenance for these fixtures and for making the fixtures vandal-resistant, such fixtures and diffusers are difficult to design since significant tradeoffs are necessary in order to meet all desired conditions.
One particular application for such improved design is the needed replacement of the existing fluorescent fixtures in the cars of the London subway system. Such cars have open fluorescent fixtures disposed in two parallel paths along the car ceiling. The fixtures have no diffusers of any kind and the lamps in the fixtures may be readily broken either accidentally or by vandals. Further, the glare of the lamps is unpleasant and the lamps provide levels of light which are considered excessive for normal reading. The lighting effect is not aesthetic to the viewer, in general. The ballasts for the lamps are also generally difficult to reach for purposes of servicing.
Other prior vehicle lighting systems which integrate the air circulation system of the vehicle with the lighting system do not provide direct/indirect light with reduced glare and limit downward velocities.