Safety lamp with noctilucent lens holder
BACKGROUND OF THE INVENTION 
     This invention relates to lamps and is particularly applicable to safety lamps which are used by miners attached to their helmets. 
     Usually, when a miner&#39;s lamp is turned off because of a pit accident, it is very hard to find his position because of the darkness inside the mining pit. If there is a glimmer light by the miner, it is easier to find the position of the victim of a pit accident. 
     It is known for miners to have luminous paint painted on the surface of their helmets in order to assist in finding the worker when the worker&#39;s lamp is turned off by a pit accident. However, such luminous paint painted on the surface of a helmet wears off during the passage of time. Also, because the light from the lamp is directed forwardly, little light is received by the helmet or the luminous paint thereon and the luminous quality quickly loses any power. 
     SUMMARY OF THE INVENTION 
     An object of this invention is to provide an efficient luminous source suitable for use by miners or others. Therefore, the invention provides a lamp provided with a part, preferably the lens holder, which is normally illuminated by the light source, which is made of luminous material, preferably luminous resin. 
     Since the lens holder will normally be illuminated by the lamp bulb and the luminous material will not be abraded away like paint, the luminous source will retain its presence and strength to be always available when needed. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     One embodiment of the invention will now be described by way of example only with reference to the accompanying drawings of which: 
     FIG. 1 is the perspective of a lens holder of a lamp in accordance with the invention, and 
     FIG. 2 is a perspective view of the lens holder attached to a lamp and battery. 
    
    
     DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT 
     A lens holder 2 of a safety lamp 1 is composed of 80% to 90% of Acrylonitrile Butadiene Styrene resin and 10% to 20% of luminous material (powder of paint) such as ZnS-Cu and CaS-Bi so that the lens holder is noctilucent. 
     The lens holder, composed of the luminous resin, will keep receiving light from the lamp bulb as long as the lamp is turned on. 
     In the case of a pit accident, with the lamp going off the lens holder will instantly give a noctiluent light. Since the lens holder 2 receives light whenever the lamp is turned on, the luminous property of the noctiluent material of which the lens holder is made is semi-permanent. The noctiluent lens holder will give enough light so that either the worker will be able to find the way by himself in case of lamp failure, or the researches of the rescue team will be facilitated by the emission of the noctilucent light.