An illumination device featuring a reflective coating on its surface, usually applied to the globe of the bulb, influences the directionality and quality of the emitted light. The metallic layer acts as a reflector, redirecting light output. A common application is in settings where controlled light projection is desired, such as theatrical lighting or specialized task lighting.
The application of a reflective material provides several advantages. It allows for more efficient light utilization by focusing illumination where it is needed, reducing wasted light dispersion. Historically, such designs have been employed to enhance the intensity of light or to create specific lighting effects. They are also useful in situations where backlighting or glare needs to be minimized, increasing visual comfort. The material can also affect the heat management of the device.