Difference Between LCD and LED?: A Detailed Comparison

One of the most heated debates in the tech world is comparing LCD and LED. LCDs pioneered electronic displays, signaling a shift from the bulky Cathode Ray Tube screens to their compact and slim profile. When the more advanced LEDs came into the picture, LCDs became almost obsolete. Go to the nearest appliance shop and you won’t find any LCD TVs anymore.

However, LCDs and LEDs are more similar to one another than you might think. Technically, LEDs are also LCDs. How did that happen? Read on to learn more.

Importance of understanding the differences between them

While both displays serve the same purpose–that is, to display digital media–they differ significantly when it comes to performance, energy efficiency, uses, and cost. Understanding their differences will allow you to make informed decisions based on your preferences, budget, and purpose of use.

Understanding LCD (Liquid Crystal Display) Technology

LCD or Liquid Crystal Display uses cold cathode fluorescent lamps (CCFLs) as a light source to light up liquid crystals and create images. It was invented by RCA Laboratories in 1964. Still, it was only in the 70s when the twisted nematic (TN) panel technology that manufacturers began using LCD in small devices such as watches and calculators.

In the late 80s, Japanese manufacturers headed by Sharp started using the display in full-color, full-motion screens. And in the following years, LCDs were widely used TV sets and computers.

How LCDs work

An LCD is composed of six layers: a polarizing filter film (vertical axis), a glass substrate with ITO electrode, twisted nematic liquid crystal, a glass substrate with common electrode film, a polarizing filter film (horizontal axis), and the light source. When the electric current reaches the liquid crystal layer, the twisted nematics will untwist themselves to varying degrees, depending on the voltage. TNs have a predictable reaction to current, making them suitable for regulating light passage.

Pros and cons of LCD technology

Pros

  • Color Accuracy: LCDs can reproduce colors accurately, making them suitable for designing graphics and editing photos.
  • Suitable for Indoor Use: LCDs are perfect for indoor installation with controlled lighting conditions
  • Suitable for Smaller Applications: LCD screens are perfect for smaller devices, such as smartphones, tablets, and digital watches. This will make the devices more affordable for a wide range of consumers.
  • High pixel density, high definition picture or video display;

Cons

  • When LCD is spliced into a large screen, there will inevitably be borders between panels, which affect the visual viewing experience.
  • Limited Viewing Angles: LCDs have limited viewing angles, so image quality may change when viewed from an off-centered angle. This may become an issue in applications where viewers look at the display from different angles.
  • Lower Contrast Ratio Compared to LED: Since LCDs use CCFLs as a light source, they have lower contrast ratios compared to LEDs. This results in a less pronounced contrast between dark and light pots, affecting the overall crispness of the image.
  • Poor Energy Efficiency: CCFLs only have one level of brightness throughout the display, resulting in higher power consumption as compared to LEDs that can be individually adjusted. 
  • Slower Response Time: Compared to newer display technologies, LCDs may show a slower response time, resulting in blurred images especially when showing high-action content.

Introduction to LED (Light Emitting Diode) Technology

LED (light-emitting diode) displays use thousands of semiconductors as light sources. Because each LED is independent of one another, their brightness levels can be adjusted to form a wider array of colors. This results in higher quality and consistent image reproduction throughout the display.

How LEDs Work

As previously mentioned, LED displays belong to a subset of LCDs in that they also illuminate a layer of liquid crystal to generate color. The only difference is what they use as the light source. LEDs come in red, green, and blue colors. When combined, these primary colors can produce thousands of other colors.

Pros and cons of LED technology

Pros

  1. High Contrast Ratio: The ability of LEDs to be controlled individually results in a higher contrast ratio in LED displays. This means that LED screens have deeper black and brighter whites compared to LCDs.
  2. Viewing Angles: LEDs illuminate the display more consistently, maintaining the image quality at any viewing angle.
  3. High Brightness Levels: LED screens are backlit by multiple LEDs instead of one big light source, increasing the display’s brightness level.
  4. Energy Efficiency: LEDs consume less energy compared to the CCFLs.
  5. Long Lifespan: LEDs have a lifespan of up to 100,000 operating hours or 10 years. In comparison, CCFLs can only last up to 40,000 hours.

Cons:

  1. Higher Upfront Cost: LED displays are more expensive than LCDs because it is a newer technology.
  2. Harder to Produce: LEDs are more difficult to produce because of the complexity of the process.

LED vs. LCD

The difference between LED and LCD
Feature LED LCD
Display Quality
Display method LED displays emit light on their own Additional light sources are required to illuminate the crystal solution to display images
Brightness High brightness, both for indoor and outdoor Low brightness, only indoor use
Splicing effect It is continuous after splicing There are borders between the panels after splicing
Contrast Ratio Higher contrast ratio due to consistent backlighting. Lower contrast ratio because of inconsistent lighting.
Color Reproduction Can produce every possible color with RGB LEDs. Less vibrant colors due to white CCFL backlighting.
Viewing Angles Consistent image quality at any angle. Limited viewing angles with quality loss.
Energy Efficiency
Power Consumption Adjustable brightness levels for lower consumption. Constant brightness results in higher consumption.
Lifespan Up to 100,000 hours or about 10 years. Up to 40,000 hours or about 5 years.
Cost
Initial Investment Higher due to developing technology. Lower due to easier manufacturing.
Long-term Expenses Energy efficiency and long lifespan reduce costs. Higher energy use; expensive maintenance.
Applications and Use Cases
Outdoor Signage High brightness and durability are ideal for outdoors. Not typically used for outdoor signage.
Digital Billboards Suitable for dynamic media with high resolution. Less commonly used for high-resolution media.
Indoor Displays Bright colors for installations with limited lighting. Commonly used in controlled lighting conditions.
Television Sets Less common due to higher cost. More commonly used for affordability.
Computer Monitors Used when high-definition is required. Perfect choice for standard requirements.
Mobile Devices Used in flagship models for better display quality. Used in mid-range models for competitive pricing.
Factors to Consider in Choosing a Display
Purpose of the Display Ideal for dynamic content and various lighting conditions. Suits static content in controlled environments.
Budget Constraints Higher initial cost but consider long-term savings. Lower initial cost but higher long-term expenses.
Environmental Considerations Adaptable to outdoor and indoor environments. Best for indoor use with controlled lighting.
Energy Efficiency Requirements Consumes less power, size affects consumption. Generally consumes more power.

Display Quality

Display Method

  • LED: LEDs produce light on their own. LED screens are composed of red, green, and blue LEDs arranged in a specific pattern. These three are combined to form a wider spectrum of colors to shine a light on the liquid crystal layer and form images.
  • LCD: LCDs require a separate light source, often in the form of fluorescent lights (CCFLs). Unlike LEDs where each pixel illuminates on its own, LCDs use twisted nematics to control light passage and form images.

Brightness

  • LED: Since LEDs produce their own light, they have complete control over the brightness levels across the display. This high brightness feature allows LED displays to adapt to any environment, whether indoor or outdoor.
  • LCD: LCDs rely on CCFLs and twisted nematics to regulate light passage. This may result in inconsistent brightness levels across the display. Because of this, LCDs are more suitable in indoor installations where there is controlled lighting.

Splicing Effect

Splicing effect refers to the seamlessness of the display formed by joining two panels together.

  • LED: With LED screens having individually controlled pixels, they can be tiled together seamlessly without losing picture quality or exhibiting inconsistencies in color and brightness across the display.
  • LCD: Tiling together LCDs require using ultra-thin bezels to achieve a seamless look. However, the part where the panels meet may still be visible, affecting image quality and appearing disconnected.

Contrast ratio

  • LED: LEDs offer consistent backlighting across the screen, hence, the higher contrast ratio compared to LCDs. A higher contrast ratio means deeper blacks and brighter whites.
  • LCD: CCFLs offer inconsistent lighting, which may result in a lower contrast ratio.

Color reproduction

  • LED: LEDs screens have red, blue, and green LEDs. By mixing them, LED displays can produce every possible color.
  • LCD: LCDs only have white CCFLs for backlighting. This may affect the vibrance of the colors it can reproduce.

Viewing angles

  • LED: The arrangement of the LEDs inside the display produces a consistent image quality across the display, at any angle.
  • LCD: LCDs have limited viewing angles because of how the fluorescent lights are installed in the back, causing images to lose quality when viewed from a different angle.

Energy Efficiency

Power consumption

  • LED: LEDs have adjustable brightness levels. This allows optimization across the display for lesser energy consumption.
  • LCD: CCFLs cannot be adjusted. The constant brightness level means more energy is consumed in the long run.

Lifespan

  • LED: LEDs can last up to 100,000 hours, or about 10 years.
  • LCD: LCDs can only last up to 40,000 hours, or about 5 years.

Cost

Initial investment

  • LED: As LED technology is still developing, the process to make them isn’t as streamlined as in LCDs.
  • LCD: LCDs are easier to manufacture, hence, the cheaper price tag.

Long-term expenses

  • LED: LED displays may be more expensive than others, but their energy efficiency and long lifespan will allow you to save money in the long run. Their maintenance is also easier as dead LEDs can be replaced individually.
  • LCD: LCDs are cheaper but have a higher energy consumption. Their maintenance could also be expensive as a damaged fluorescent light could mean replacing the whole display altogether.

Applications and Use Cases

LED displays

  • Outdoor signage – LED displays are commonly used for outdoor signage because of their high brightness level and durability. They are suitable for billboards and signage.
  • Digital billboards – High-resolution LED screens are suitable for displaying dynamic media such as videos and animations.
  • Indoor displays – The bright colors produced by LEDs are suitable for indoor installations with limited lighting options.

LCDs

  • Television sets – LCDs are more commonly used in TV sets for their affordability.
  • Computer monitors – Personal computers and workstations don’t usually require high-definition displays, making LCDs a perfect choice.
  • Mobile devices – While flagship smartphones and tablets use LEDs, mid-range models use LCDs because of competitive pricing.

Factors to Consider in Choosing A Type of Display

If you’re having a hard time deciding which display to choose, consider these factors:

Purpose of the display

What type of content are you going to display? LED displays are perfect for animations and videos. Meanwhile, LCDs suit static content such as photos. You should also consider location. LED displays suit indoor and outdoor installations because of their high brightness levels, ability to adjust in any lighting conditions, and durability. Meanwhile, LCDs are more suitable for indoor installations with controlled lighting conditions.

Budget constraints

LEDs are more expensive than LCDs. However, you should consider their energy efficiency, maintenance, and lifespan. If the quality of the image will significantly affect your content, consider investing in an LED display. If not, LCDs are perfectly fine.

Environmental considerations

Whether outdoors under the sun or indoors in ambient lighting, LEDs can display a high-quality reproduction of your content. If your display will be mostly indoors, LCDs should be enough.

Energy efficiency requirements

LEDs are known to consume less power than LCDs. Additionally, the size of your display matters, as this will dictate how much energy it will consume.

Conclusion

While we all grew to believe that LEDs and LCDs couldn’t be more different than night and day, the reality is they’re more similar than we think. The only major difference is their light sources. However, this difference has significant effects on how they display content, from the sharpness of every detail to the consistency of the colors. In some ways, one is better than the other. It’s up to you to choose which one suits your needs best.

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