On home appliances, it is often necessary to display numbers and words to convey information, such as the current time on the clock or the temperature information on the kettle, etc. The two most commonly used types of displays are LED displays and LCD displays. This article will compare the advantages and disadvantages of LED displays and LCD displays and provide a two-step method to determine whether this product is an LCD or LED display.

Introduction to LCD display

　　LCD displays are the most common displays in daily life, used in various devices from mobile phone screens to home appliances. Whether it is a color or black and white LCD display, the principle remains the same. There are two main components within an LCD display:

• Backlight module
• Liquid crystal panel

　　The general structure of the display can be illustrated in the following figure. The liquid crystal panel itself does not emit light. To view colors on the LCD display, a backlight module is placed behind the liquid crystal panel, emitting light through it. Typically, the backlight module emits white light, which can be controlled by the liquid crystal panel to display various colors on the front of the LCD display. This is the fundamental principle of LCD displays.”

Common LCD display

There are two most common LCD display:

• Black and white LCD display.
• Full color LCD display

Common LCD Displays- Monochrome LCD displays

　　Black-and-white LCD displays are widely used in a variety of low-cost products, and the picture above shows a black-and-white LCD display used in a scientific calculator.

Advantages of monochrome LCD displays:

1. Compact Information Display:
   • Monochrome LCD displays can show information in a very compact manner. Each display point on the calculator, as shown below, is positioned close to each other, allowing for high-resolution text display.
2. Power Saving:
   • Black-and-white LCD displays operate with lower power consumption compared to full-color LCD displays. They are often preferred for products that do not require full-color capabilities and need to manage power consumption effectively.
3. Cost-Effectiveness:
   • When the requirement is to display numbers or a few icons, using a black-and-white LCD display is much cheaper than opting for a full-color LCD display. Therefore, it is commonly utilized in a wide range of consumer products.
4. Clarity:
   • Monochrome LCD displays offer sufficient contrast and clarity for indoor use.

Disadvantages of monochrome LCD displays:

1. Limited Viewing Angle for Outdoor Use:
   • Black-and-white LCD displays have a small viewing angle, making them less suitable for outdoor applications. When viewed from the front, the display is the clearest. However, due to the characteristics of LCD panels, the clarity diminishes when viewed from the sides. Outdoor usage is also affected by strong light, resulting in reduced clarity. In contrast, LED displays do not have viewing angle issues due to their inherent luminosity.
2. Limited to Monochrome:
   • Monochrome LCD displays can only be used to display a single color. If multi-color applications are required, upgrading to a full-color LCD display becomes necessary, which significantly increases the cost. On the other hand, LED displays can easily incorporate different colors without a significant cost increase.”

Common LCD displays vs. Full color LCD displays.

　　The most common display in daily life is a full-color LCD display. Whether it’s on your mobile phone or computer, you can find a full-color LCD display. Full-color LCD displays achieve higher resolution and a wider color range through precise adjustment of the LCD screen’s transmittance. The following picture shows a computer screen with a damaged liquid crystal, with the broken area displaying normal high-resolution graphics.”

Features of the LED display

　　This article provides the structure and basic introduction of the LED display. Compared with LCD displays, LED displays have self-illumination characteristics, which result in high outdoor visibility and brightness, as well as no viewing angle problems. LED displays are similar to black and white LCD liquid crystals, and the display information must be designed in advance and cannot be arbitrarily transformed. The price of LED displays falls between full-color LCDs and monochrome LCDs, and if properly designed, they can save costs while achieving optimal display performance.

Two-step differentiation between LED displays and LCD displays?

　　The following process can be used to determine whether the display in your hand is an LCD display or an LED display:

1. Observe if the information on the display is static. If it is not static, then it is not an LED display.
2. If the displayed information is static, turn on the monitor and check if there is a backlight in the area where nothing is displayed.”

Comparison of LED displays and full-color LCD displays on computer screens

Schematic diagram of the contrast between the LED display and the monochrome LCD display

Conclusion

　　This article provides a brief introduction to the basic principles, advantages, and disadvantages of two common LCD displays. It also offers two steps to quickly determine whether the display in hand is an LED display. Product designers can follow these steps to identify the type of display used in the product during observation.”