What Is an LCD TV?
An LCD TV is a flat panel television that uses the same LCD (liquid crystal display) technology found in cellphones, camcorder viewfinders, and computer monitors. LCD panels are made of two layers of a glass-like material, which are polarized and glued together. One of the layers is coated with a special polymer that holds the individual liquid crystals. Electric current is passed through the individual crystals, which allows the crystals to pass or block light to create images. LCD crystals do not produce light. An external light source, such as fluorescent or LED light bulbs, is needed for the image created by the LCD to become visible to the viewer. LCD TVs can be made very thin, allowing them to be hung on a wall or placed on a small stand on top of a table, desk, dresser, or cabinet. LCD TV technology is resolution agnostic. In other words, LCD TVs can display a variety of resolutions, from 480p up to 8K, and, in the future, even higher depending on how TV makers want to provide consumers. It is also important to note that LCD TVs display images progressively.
LCD and LED
When shopping for a new TV, you will encounter many TVs labeled as LED TVs. The LED designation on a TV refers to the LCD TV’s backlighting system, not the chips that produce the image content. LED TVs are still LCD TVs. These TVs use LED backlights rather than the fluorescent-type backlights of most other LCD TVs.
LCD and QLED
LED isn’t the only label that can be confusing with regards to LCD TVs. Another label that you might encounter is QLED, which is used mostly by Samsung and TCL. Vizio, on the other hand, uses the term Quantum. These labels refer to TVs that use quantum dot technology to improve color performance. Quantum dots are an added layer of nano-sized particles, placed between an LED backlight and the LCD display layer in an LCD TV. The dots are clustered in different sizes, with each size producing a specific color range when hit by the light from LEDs. The result is richer colors that can be displayed on an LCD TV screen, especially images at higher brightness levels.
LCD and OLED
Although LCD is the core technology used in most TVs, there is a type of TV which is not a variant of LCD, OLED. OLED TVs use a technology that consists of self-emitting pixels (similar to the now-discontinued plasma TV tech). It uses less energy and can be made almost paper-thin. Each pixel can be turned on and off individually, allowing OLED TVs to produce absolute black and more brilliant colors than either plasma or LCD. However, the main drawback is an overall lack of brightness. LCD TVs can produce higher brightness levels.
LCD and Plasma
LCD and plasma TVs share one thing in common. Both are flat and thin and can be wall-mounted. However, inside those thin cabinets, these TVs employ different technologies to display images for TV viewing. Plasma TVs use pixels made of self-emitting phosphors (a backlight isn’t required) to produce images. The advantage over LCD TVs is that each phosphor can be turned on and off individually, producing deeper blacks. On the other end, plasma TVs can’t produce images as bright as an LCD TV. In addition, plasma TVs are subject to burn-in if a static image is displayed on the screen for too long a time period.
Video Frame Rate vs. Screen Refresh Rate
When shopping for an LCD or LED/LCD TV, you will hear terms like 60 Hz, 120 Hz, 240 Hz, MotionFlow, ClearScan, and more. What does this mean, and is it important when considering the purchase of an LCD or LED/LCD TV? Those numbers and terms refer to how an LCD TV can handle motion. Although LCD TVs can produce bright, colorful images, one problem these TVs had from the outset is that the motion response isn’t that natural. Without some enhancement, fast-moving images on LCD TVs can exhibit lag or jerkiness. Over the years, several technologies have been employed that have improved things to varying degrees. One option is to increase how often the screen refreshes the image on the screen. For example, 60 Hz means that the screen refreshes 60 times a second, 120 Hz refreshes at 120 times a second. Other techniques are also used, such as blacklight scanning (flashing the backlight at a high rate) and frame interpolation (inserting black or intermediate frames between each actual frame). The technique used varies depending on the brand and model of TV.
Before You Buy an LCD TV
Before you purchase an LCD TV, in addition to the core technologies discussed above, there are other things to take into consideration so that a specific brand and model is right for you.
Screen size and seating distance: TV screen sizes are getting larger. If you’re thinking about getting a big screen TV, make sure it will fit in your room and look good at your seating distance. Viewing angle: One weakness of LCD TVs is the relatively narrow viewing angle. You get the best results at the center seating position and good results within 30 to 45 degrees on either side of the center spot. However, as you move farther to either side, you’ll notice picture fading and color shifting. OLED and plasma TVs are less prone to this problem. Flat screen or curved screen: Although not as numerous as they were a few years ago, Samsung still makes a limited number of curved-screen TVs. Still, there are things to consider, such as susceptibility to room glare and viewing angle. Connections: Depending on the brand and model of the TV, the type and number of connections may vary. Generally speaking, you can connect both an old VCR and the latest Blu-ray Disc player. If you have older analog gear (such as a VCR or DVD player without an HDMI connection), there are a growing number of TVs (both LCD and OLED) that may have limited options. Smart TV: Most LCD TVs are equipped with some smart features. This allows you to stream content, such as Netflix, directly to your TV without an external device, provided the TV is connected to the internet. HDR: HDR is available on some LCD and OLED TVs. This feature allows you to view content that is specially coded with enhanced brightness information. Sound options: All LCD TVs come with built-in speakers, but the sound quality is often not good. If the sound quality isn’t satisfying, connect the TV to an external sound system, such as a soundbar or a home theater audio system. All LCD TVs, except for some with small screen sizes, can connect to an external audio system. Most have analog and digital connection options. Still, depending on the brand and model, only the digital connection option may be offered.
