In this blog post, we will look at how lighting technology has evolved to become smarter and more efficient, from incandescent bulbs to fluorescent lamps, LEDs, and smart lighting.
Lighting fixtures that use electrical energy have been continuously improved since the invention of the incandescent light bulb to increase the luminous efficiency and the life of the fixtures. Luminous efficiency refers to the ratio of power consumption to light conversion. Light here refers to visible light, which is a type of electromagnetic wave between infrared and ultraviolet light. Modern lighting fixtures are becoming more efficient and environmentally friendly, and various technological innovations are being made.
Incandescent light bulbs have a simple structure in which a filament is placed in a round glass bulb and filled with an inert gas. When voltage is applied to the filament, some of the energy from the heated filament is emitted in the form of electromagnetic waves. The wavelength of these electromagnetic waves has a continuous spectrum, of which light accounts for about 10%, and the rest is infrared, which is a form of heat. Since most of the power input to the bulb is released as heat, the luminous efficiency is very low, and the filament is easily broken due to high temperature, so the life of the incandescent bulb is also short. Increasing the voltage applied to the bulb increases the temperature of the filament, which increases the proportion of light but shortens the life. Due to these problems, incandescent bulbs are gradually being replaced by other high-efficiency lighting fixtures.
Fluorescent lamps contain mercury and inert gas in a cylindrical glass tube with filaments attached to both ends. Ultraviolet rays are generated when the electrons emitted from the filaments collide with the mercury particles. When these ultraviolet rays hit the fluorescent material applied to the inside of the fluorescent lamp, they are converted into light. At this time, the color of the light varies depending on the type of fluorescent material, and the conversion efficiency of converting ultraviolet rays into light also affects the luminous efficiency of the fluorescent lamp. Fluorescent lamps do not directly obtain light from the filament, so the heating temperature can be lowered, and the same brightness of light can be produced with about 30% less power consumption than incandescent bulbs. In addition, they emit less infrared radiation than incandescent bulbs and last five to six times longer. However, fluorescent bulbs also contain mercury, which poses environmental and safety issues when they are disposed of.
Light-emitting diodes (LEDs) are made by bonding two types of semiconductors, p-type and n-type. When voltage is applied, a certain voltage difference is generated between the two semiconductors. At this time, electrons moving between them emit energy equal to the voltage difference as light. The required voltage and the amount of energy emitted differ depending on the compound that makes up the two bonded semiconductors. The light emitted from the light-emitting diode has a single color as the wavelength of the emitted light is determined by the size of this energy. LED lighting is very popular because it has low energy consumption, a long lifespan, and can provide light in various colors.
In order to use a light-emitting diode as a light-emitting element for lighting, it must be able to emit light that covers the entire visible light spectrum. So, a fluorescent material is coated on a light-emitting body that emits a single color of light, making it emit light like a fluorescent lamp. However, since the light-emitting diode does not have a heating element like a filament, it has a longer lifespan and lower energy loss than a fluorescent lamp. Thanks to the development of LED technology, it is now the main lighting fixture that replaces incandescent bulbs and fluorescent lamps, and is used in various applications.
The development of lighting fixtures that use electrical energy continues, and recently, smart lighting systems have emerged to further improve the efficiency and convenience of lighting fixtures. Smart lighting uses IoT technology to allow users to control lighting remotely, and automated lighting control functions can maximize energy savings. These technological advancements not only increase the efficiency of lighting fixtures, but also contribute greatly to improving the quality of life of users.
