The Truth About So-Called LED TVs

Don't get confused when buying your next TV

There has been a lot of hype and confusion surrounding the marketing of "LED" TVs. Even many public relations representatives and sales professionals that should know better are falsely explaining what an LED TV is to their prospective customers.

The following information applies TVs made by a variety of manufacturers including, but not limited to Hisense, LG, Panasonic, Samsung, Sony, TCL, and Vizio.

LCD vs LED

Overall Findings

LCD
  • Can be less expensive.

  • Uses more energy.

  • Thicker TV.

  • Duller, dimmer picture.

LED
  • Thinner TVs.

  • Brighter, more vibrant picture.

  • More energy efficient.

  • Wider range of screen sizes.

  • Last longer.

How different really are LCD and LED TVs? Are they different at all? In truth, they really are too similar to fully compare. The main difference between these two comes down to the backlighting.

All TVs have lighting behind the screen to illuminate the picture and make it visible. The light is key. As you may know, LCD stands for Liquid Crystal Display, and it refers to how the picture is produced on the TV. In TVs with the LCD designation, the lighting behind the screen is usually some form of a fluorescent bulb. The backlighting on a TV can literally burn out, in some cases.

LED TVs are LCD TVs, but they're branded differently. That's because, instead of a more traditional lighting element, LED TVs hare backlit by LEDs(Light Emitting Diodes). As you know from regular light bulbs, LEDs tend to be brighter, more compact, and longer-lasting. In addition to that, they're more energy-efficient. LED TVs still have a liquid crystal display, but they're lit by an all-around better system, using LEDs.

LCD TVs

Advantages
  • Thinner than tube TVs.

  • Usually simpler than LED TVs.

Disadvantages
  • Florescent lighting takes more room.

  • Florescent lighting uses more energy.

  • Florescent lighting isn't as bright.

  • Florescent lighting doesn't last as long.

LCD TVs are named after their liquid crystal display, but what exactly does that mean? It's hard to explain thoroughly without getting too technical, but there is a fairly basic way to get the idea.

A liquid crystal display is made of two sheets of glass or glass-like transparent material. Between them is a layer with individual liquid crystals. When an electric current is passed through the crystals, they allow and block different colors of light through. This can be used to create pictures which change rapidly as the electric current changes.

The crystals don't emit any light on their own, so a light source needs to be placed behind them to pass light through. In the case of the original generation of LCD TVs, that light source was usually fluorescent bulbs.

While LCD TVs were much thinner than their tube-based ancestors, they're still limited by the size of their lighting element.

The fluorescent bulbs are also less efficient than LEDs, and they produce a lower quality light with less dynamic options.

LED TVs (aka LED/LCD TVs)

Advantages
  • LEDs allow LCD TVs to be made thinner and lighter.

  • LEDs help produce more vibrant color.

  • LEDs are more energy efficient.

  • LEDs last longer than traditional lighting.

Disadvantages
  • Can be more expensive.

  • Often include Smart TV components, for better or worse.

LED TVs are essentially the same as LCD ones. Instead of florescent lighting being used to illuminate the crystals, LED TVs use LEDs(light emitting diodes).

LEDs are smaller than florescent lighting, allowing LED TVs to be much thinner and lighter than LCD ones. They also use significantly less energy and produce less heat.

LED TVs make better candidates for hanging on a wall, and the different lighting solution has allowed them to explode to massive sizes, thanks to lower energy consumption and the ability to spread LED lighting without dramatically increasing thickness of the TV.

LEDs also last much longer than previous lighting solutions. LEDs are known for their exceptionally long lifespan in other applications, like home lighting, and TVs are no exception.

For more specifics on the backlighting process needed for LCD TV, read Demystifying CRT, Plasma, LCD, and DLP Television Technologies.

To be technically accurate, LED TVs should be labeled and advertised as LCD/LED or LED/LCD TVs.

Two Types of LED Lighting

There are currently two ways that LED backlighting is applied in LCD TVs, Edge Lighting and Direct Lighting.

LED Edge Lighting

Edge Lighting consists of a series of LEDs are placed along the inside edges of the LCD panel. The light is then dispersed across the screen using "light diffusers" or "light guides."

  • The advantage of this method is that the LED/LCD TV can be made very thin.
  • The disadvantage of Edge lighting is that black levels are not as deep and the edge area of the screen has a tendency to be brighter than the center area of the screen.
  • Sometimes you may see what is referred to as "spotlighting" in the corners of the screen, and/or "white blotches" scattered across the screen. When viewing daylight or lit interior scenes, these effects are not usually noticeable. However, they can be noticeable when night or dark scenes in a TV program or movie are viewed.

LED Direct Lighting

Direct or Full-Array (also referred to as Full LED) consists of several rows of LEDs placed behind the entire surface of the screen.

  • The advantage of the full-array backlight is that it provides a more even, uniform, black level across the entire screen surface without white blotches or corner spotlighting.
  • Another advantage is that these sets may employ "local dimming" (if implemented by the manufacturer). Full-Array Backlighting combined with Local Dimming is also referred to as FALD.

Below is an example of a TV that features Full-Array Backlighting with Local Dimming.

vizio-full-array-zones-large.jpg
Vizio Full-Array Active LED Zone Illustration. Image provided by Vizio, Inc.

If an LED/LCD TV is labeled as Direct Lit, this means that it doesn't include local dimming, unless there is an additional qualifier. If an LED/LCD TV incorporates local dimming, it's usually referred to as a Full Array Backlit Set or is described as Full Array with Local Dimming.

When local dimming is implemented groups of LEDs can be brightened or dimmed independently within certain areas of the screen (sometimes referred to as zones). This provides more control of the brightness and darkness for each area, depending on the source material being displayed.

Sony's Backlight Master Drive provides dimming of each individual LED.

Another variation on full array backlighting with local dimming is Mini-LED. Mini LEDs work like "standard" LEDs but are much smaller. This means instead of just a dozen or a few hundred LEDs, Mini-LEDs can number in the thousands and can be grouped within hundreds of zones.

This allows even more precise brightness and contrast control for both bright and dark object elements, such as eliminating white bleeding from bright objects on black backgrounds.

TCL's Quantum Contrast labeled TVs are examples that use mini-LED technology.

TCL Mini LED Chart
TCL

Local Dimming In LED Edge-Lit LCD TVs

Some edge-lit LED/LCD TVs also claim to feature "local dimming."

  • Samsung uses the term micro-dimming. 
  • Sony uses the term Dynamic LED (on TVs that don't have Blacklight Master Drive).
  • Sharp refers to their version as Aquos Dimming. 

Depending on the manufacturer the terminology used may vary. However, the technology employed consists of varying light output using light diffusers and light guides, instead of large numbers of LEDs directly behind the screen. This method is less precise than FALD.

If you are considering an LED/LCD TV, find out which brands and models use Edge or Full Array backlighting and see which type of LED backlighting looks best to you.

More Tricks Up LED's Sleeve

Because of the LED technology, a much wider range of options are open to the TVs that employ it as a backlighting system. LEDs are infinitely more flexible than the traditional florescent lighting elements. As a result, LEDs have opened the door to many of the top innovations in TVs over the last several years, including more than a few that have drastically improved picture quality. These are some of the innovations and features to consider in purchasing an LED TV.

LEDs and Quantum Dots

Another technology that is being incorporated into a growing number of LED/LCD TVs is Quantum Dots. Samsung refers to its Quantum Dot-equipped LED/LCD TVs as QLED TVs, which many confuse with OLED TVs. However, don't be fooled—the two technologies are different.

In brief, Quantum Dots are man-made nanoparticles that are placed between an Edge-Lit or Direct/Full-Array LED Backlight and the LCD Panel. Quantum Dots are designed to enhance color performance beyond what a LED/LCD TV can produce without them.

Samsung is spearheading a move to develop TVs that combine Quantum Dots with OLED. This is referred to as QD-OLED.

Digital Signage and Micro-LED

The only true LED-only video displays, are the ones you see in stadiums, arenas, other large event venues, "high-res" billboards, a small number of cinema screens, video walls, that employ technologies such as MicroLED in which the "LEDs" display image content directly by generating the light, the color, an image content.

LG MicroLED Video Display Demo
LG

LED Use in DLP Video Projectors

LED lighting is also being used in DLP and to a lesser extent, in LCD video projectors.

An LED light bulb(s) supplies the light source instead of a traditional lamp. In a DLP video projector, the image is produced in a grayscale form on the surface of the DLP chip, in which each pixel is also a mirror. The light source (in this case an LED light source made up of red, green, and blue elements) reflects light off of the DLP chip's micromirrors and is projected onto the screen.

Using an LED light source in DLP video projectors eliminates the use of a color wheel. This eliminates the DLP rainbow effect (small color rainbows that are sometimes visible in a viewers' eyes during head movement).

Since LED light sources for projectors can be made extremely small, a new breed of compact video projectors, referred to as Pico projectors have become popular.

Video Projector LED Light Source Generic Example
NEC

LED Use In TVs, Present and Future

Since the demise of Plasma TVs, LED/LCD TVs are the dominant type of TVs available to consumers. OLED TVs, that use different technology, are also available, but have limited distribution (As of 2020, LG and Sony are the only TV makers marketing OLED TVs in U.S. Market), and are more expensive than their LED/LCD TV counterparts. With the refinement of local dimming and Quantum Dots, the future of LED/LCD TVs is very bright.

Final Verdict

In case you haven't already guessed, there's no reason to buy a traditional LCD TV, if you can even find one. LED is universally better. It is, after all, the next iteration following florescent lit LCD TVs, and in a rare twist for the tech industry, it moved forward with no real drawbacks. Nearly every TV you see on the market today is an LED TV. Don't worry too much about the difference now. Instead, consider some of the additional features that LED technology made possible.