Dark Sky Light Bulb
Light Bulb Types
Dark sky light bulbs or lamps are outdoor light sources that utilize shielding to lessen light pollution within a designated area. Light pollution or photopollution is what happens when an area has excessive artificial lights that may become obtrusive to a person's vision and disrupt many ecological factors such as the physiology of nocturnal animals. For example, spiders that don't mind light can effectively spin web near lampposts since it attracts many flying insects thus gaining an unfair advantage over spiders who don't like the light. The adverse effects of light pollution include glare, sky glow, light trespass, decreased visibility at night, light clutter, blood pressure elevation as well as circadian rhythm disruption.
Manner of Operation
Dark sky lamp units are usually just your typical bulb, often a CFL spiral bulb housed inside a special shield. This special housing can effectively prevent light from spreading in other direction except on the one intended. They are usually incorporated with the main function of preventing light from shining upwards and there are even some lamps designed to stop light from shining upwards as well.
Dark sky bulbs are used in many situations where decreasing light pollution is the main concern or if you just want light to be pointed at the ground and not anywhere else. Generally, they are designed with that purpose in mind and they do it well as over-illumination can increase the risk of worker fatigue, stress, and decrease in sexual function as well as increased anxiety levels. Dark sky bulbs can effectively prevent light from travelling upward but they can also be used in places where horizontally shining light or light shining outward needs to be kept in check so as to prevent any untoward effects, such as with the migration of turtles and birds.