Lighting has evolved over the course of human history, from natural light to the creation of artificial light. From ancient torches to modern LEDs, various light sources have evolved and played an important role in human life, emotions, and the aesthetics of architecture.
Lighting has evolved with humanity. In the distant past, humans lived solely by sunlight, moonlight, and starlight, relying on the light provided by nature. Over time, however, we gradually created artificial light and gained control over it. Today, light is not only an essential part of our daily lives, but it also plays an important role in controlling our emotions and beautifying the appearance of buildings and structures. In this blog post, we’ll take a closer look at the history of lighting and the different sources of light.
The history of lighting began in primitive times, when humans lit materials such as torches, fire cores, and earthenware lanterns. These were mainly used as a source of light for indoor illumination. The Middle Ages saw the development of candlelit lighting using candlesticks and arc-shaped lanterns, while the modern era of the 18th century saw the emergence of oil-based lighting such as oil lamps and gas lamps. As technology progressed, gas lanterns became more and more efficient, providing better illumination, and different types of burners were developed. A burner is a device that burns gas to produce light.
In 1808, Humphry Davy discovered that passing an electric current through carbon produced light, and he lit an arc street lamp in the Place de la Concorde in Paris. However, the light was too intense and required constant adjustment, so it was not widely used. In 1879, Thomas Edison invented the incandescent light bulb using a filament, which was commercialized by Edison and Joseph Wilson Swan. In 1894, a carbon filament bulb made from cellulose was invented, but the carbon evaporated at high temperatures, causing the inside of the bulb to blacken. In 1920, William David Coolidge succeeded in creating a tungsten filament, which increased the lifespan of the bulb, and in 1913, Irving Langmuir enclosed nitrogen gas inside the glass bulb to inhibit the evaporation of the filament, further extending the lifespan of the bulb. Later, argon and nitrogen gases were enclosed in the glass bulb to increase the efficiency of the bulb, which is still used today. Today, there are more than 20,000 types of light sources, including halogen lamps, fluorescent lamps, high-pressure discharge lamps, and LED lamps.
Light sources are categorized according to how they produce light. There are three types of light sources: incandescent bulbs, which produce light by thermal radiation; fluorescent lamps, which produce light by electrical discharge; and light-emitting diodes (LEDs), which produce light by an electric field. Incandescent bulbs are light sources that produce light through thermal radiation by passing current through a filament and heating it to a high temperature. An incandescent bulb consists of a glass bulb, a filament, a sealing gas, a base, an exhaust port, an anchor, and an introduction wire. Tungsten is used for the filament because it has a high melting point and a small coefficient of expansion, so it doesn’t change shape. The containment gas is a mixture of 85% argon and 15% nitrogen. Argon is chemically stable, so it doesn’t react at high temperatures and is robust. Incandescent bulbs have a capacity of 15 W to 1500 W, an efficiency of 10 lm to 20 lm/W, and a lifespan of 1000 to 2000 hours. Incandescent bulbs have good color rendering, a warm light color, are easy to light, and can be continuously dimmed. However, they also have the disadvantages of low efficiency, high infrared radiation, high temperature, and relatively short lifespan. They are typically used for general lighting, accent lighting, and mood lighting in small spaces, while large incandescent bulbs are used for ceiling or flood lighting.
Fluorescent lamps are light sources that produce light by an electrical discharge in a gas or vapor. A fluorescent lamp consists of a fluorescent discharge tube filled with mercury and argon gas, an electrode, a light tube, and a ballast that controls the current to stabilize the discharge. Here’s how fluorescent lights work When a fluorescent lamp is switched on, current flows through the filament of the fluorescent discharge tube, which heats up and produces ultraviolet light, which stimulates the fluorescent material to emit light. The temperature inside the light tube then drops and a high voltage is generated at both ends of the ballast, causing a discharge between the filaments on both sides of the discharge tube. Ultraviolet light stimulates the fluorescent material to emit light. Fluorescent lamps have a capacity of 6W to 70W, an efficiency of 50 to 100 lm/W, and a lifespan of 8000 hours to 20000 hours. Fluorescent lamps have the advantages of easy light color control and low heat radiation, and are used for general lighting, localized lighting, and ambient lighting.
An LED (light-emitting diode) is a type of diode that emits light when current flows through it. LEDs are made by joining a P-type semiconductor and an N-type semiconductor, and when a voltage is applied, the holes in the P-type semiconductor move toward the N-type semiconductor and collect in an intermediate layer. The electrons of the N-type semiconductor move in the opposite direction, gathering in the lowest energy state of the conduction band, and then falling into the empty space of the appliance band, releasing energy. This energy is converted into light. LEDs come in a variety of forms, including bulbs, fluorescent lamps, and flat panels, and have the advantages of low power consumption, fast turn-on and turn-off speeds, long life, and clear light. It is also an eco-friendly light source. However, they are somewhat expensive and require a separate power supply. With the recent ban on incandescent bulbs in many countries, LEDs have become a popular alternative to incandescent lighting.
With the global environment and energy issues being a major social concern today, the need for economical and efficient lighting is becoming more and more important. As a result, LEDs are receiving a lot of attention as the most suitable lighting, and research is being actively conducted in various fields to improve their practicality as the next generation of lighting.
