LCD vs. LED: 5 Must Know Facts
- In a liquid-crystal display (LCD), electric currents interact with a layers of crystals to block different frequencies of light and produce colors.
- LCD technology empowers screens in home devices like a watch, smartphone or computer monitor.
- Older LCDs are backlit with cold-cathode fluorescents lamps (CCFLs).
- Most LED displays use a liquid-crystal layer with light-emitting diodes as a light source.
- Newer OLED screens produce images using only LED pixels.
Chances are, you have devices with LCD and LED screens in your home. But do you know the difference between these two display types?
Liquid crystal displays (LCD) are flat-panel screens used for displaying information or images on everything from watches to computer monitors and televisions. LCD screens feature a layer of liquid crystals sandwiched between two panes of polarized glass. Since liquid crystals don’t emit light, these screens require a backlight or reflector to produce images. Older LCD screens were backlit with fluorescent lights, which contain mercury. Newer LCD screens incorporate light-emitting diodes.
Light Emitting Diode (LED) displays can be found on cellphones, TVs, and computers. LED screens are made up of red, green, and blue LEDs that are installed in a fixed pattern. These three colors form a pixel that can display virtually any color by adjusting the intensity of the diodes used to backlight the display.
LCD vs. LED: The Key Differences Explained
People of a certain age will remember the size and heft of a cathode-ray tube TV or monitor. These heavy appliances required sturdy TV stands and were difficult to move. The liquid-crystal display TV quickly displaced its CRT-based relatives. These screens were much thinner and lighter. The smaller size made it possible to develop portable laptop computers.
LCD screens are a ubiquitous technology. Devices from watches to appliance displays use liquid crystals to share information. These crystals do not produce light on their own. A small screen like a watch may have a reflective layer that directs ambient light. A monitor or TV must be backlit by a more robust light source.
The source of the backlighting creates the distinction between LCD and LED screens. Older LCD monitors use fluorescent lights. Liquid crystals in LED screens are backlit using more efficient light-emitting diodes.
LCD vs. LED: Side by Side Comparison
| Abbreviation Stands For | Liquid-Crystal Display | Light-Emitting Diode |
| Common Applications | TVs, Monitors, and Laptops | TVs, Monitors, and Laptops |
| Backlit By | White Fluorescent | White LED |
| Local Dimming Capability | Low | High |
| Screen Burn-In Risk | None | Medium |
| Average Lifespan | 30,000 hours | 50,000 hours |
LCD Screens: A Complete Overview
Scientists have studied the properties of liquid crystals since their discovery in the late 1800s. However, it was not until the 1960s that people learned how to incorporate them in displays. In an LCD screen, two pieces of polarized glass sandwich a layer of liquid crystals. As electric currents pass through the crystalline layer, the crystals can block different light frequencies.
In a simple screen like a digital watch, the blocked light creates a black display. In a TV or computer monitor, more advanced technology allows for pixels in a wide variety of colors.
Backlit displays require a light source. The first generation of LCD screens used fluorescent lights for this purpose. These were some of the longest-lasting and efficient light sources of the time. For this reason, displays that use fluorescents continue to bear the LCD-screen label.
Like other CCFL light sources, the fluorescent lights in LCDs are manufactured using mercury. Environmental concerns led researchers to look for a better lighting option. The next generation of laptops and monitors incorporated light-emitting diodes.
LED Screens: Understanding a New Technology
LED screen technology is changing rapidly. However, most LED displays are still a variation in liquid-crystal technology. They have replaced the less efficient CCFL light source with the cool light of LEDs.
Replacing this light source has several benefits. LEDs last significantly longer than CCFLs and run more efficiently. They are a more responsive light source that offers higher clarity and contrast. For a clear picture and fast gaming, LEDs are a smart choice.
Using LEDs also alleviates some of the concerns around CCFLs. Light-emitting diodes do not contain mercury, so their disposal is less complicated. These lights are also dimmable, which can reduce eyestrain in office settings.
QLEDs
LED technology continues to evolve, producing more refined displays. The Q in QLED stands for quantum. In addition to the traditional liquid-crystal layer, these screens incorporate a film of quantum dots. These dots emit light at a molecular level for deeper colors and higher contrasts.
OLEDs
Organic LED displays represent something new in viewing technology. A traditional LED monitor is an LCD screen with an LED light source. OLED TVs do not use liquid-crystal technology. Instead, pictures come from millions of embedded LEDs. These tiny lights produce clear images on the thinnest screens on the market.
LCD vs. LED: Choosing Your Next Screen
Right now, the type of monitor you choose is a matter of personal preference. If cost is an issue, traditional LCDs offer performance levels that are adequate for most needs at a lower price. However, to work with the latest technology, you will want to consider an LED-powered display.
Technology companies are moving toward LEDs as the standard technology for TVs and computer monitors. Their efficient operation, faster response rate, and lower environmental impact make them an attractive choice. Soon, it will not be a matter of choosing between LCD and LED displays. Instead, you will have to consider what sort of LED screen you want to watch.
