Tomorrow's World

From LCD to micro LED – looking towards the future of signage

by FESPA Staff | 18/04/2024
From LCD to micro LED – looking towards the future of signage

Explaining the display technologies and new flexible uses of non-printed signage.

The European Sign Expo took place last month in Amsterdam, co-located with the FESPA Global Print Expo, where producers showcased the latest innovations and equipment in the industry. What functionality does current technology offer, and what does the future hold for signage?

LCD (liquid crystal display), LED (light emitting diode), OLCD (organic liquid crystal display), and OLED (organic light emitting diode) are all types of display technologies used in signage, each with its own characteristics and advantages.

LCD (liquid crystal display)

LCD displays use a backlight (typically fluorescent lamps or LED arrays) to illuminate a layer of liquid crystals, which manipulates light to produce images. They are known for their energy efficiency and relatively lower cost compared to some other display technologies. LCDs typically offer good brightness and colour reproduction but may have limited viewing angles compared to other technologies.

LCD is the most affordable technology, good for applications not requiring great pixel density or colour reproduction. Better for indoor settings with controlled lighting conditions. Many LED televisions are actually LCD panels backlit by LED lights. 

LED (light emitting diode)

LED displays use an array of light-emitting diodes to produce images. These diodes emit light when an electric current passes through them. LED displays are known for their high brightness, excellent colour reproduction, and wide viewing angles. They are often used in outdoor signage due to their high visibility even in bright sunlight. Therefore, they have been used on public transport vehicles and for variable messages on motorways for drivers. 

LED displays are thinner, more energy-efficient and offer longer lifespans compared to traditional LCD displays.

OLCD (organic liquid crystal display)

OLCD is a variation of traditional LCD technology that incorporates organic materials (e.g. hydrogen-carbon compounds) in its liquid crystal layer, well known in the mobile phone industry. It offers similar benefits to LCD displays but may provide improvements in areas such as flexibility and potentially thinner form factors.

OLCD technology is still in development and has the potential for applications in signage where flexibility or unique form factors are desired: for example, video can be wrapped freeform around objects.

It does not have to use glass, although it has full colour and video-rate capability. Built on low-cost plastic substrates and using flexible, high-performance organic transistors, OLCD tech avoids the rigid silicon transistors typically used in glass products, allowing supreme flexibility. Product companies can create striking designs and use it in novel ways by merging the display into the product design rather than forcing the product to adapt to the display.

OLCD is the lowest cost flexible display technology—at three to four times lower cost than flexible OLED. This is because OLCD display manufacturing uses organic rather than silicon-based thin film transistors (TFTs). Organic TFTs require a lower processing temperature than silicon-based TFTs, so the manufacturing process is less costly as it saves on energy bills.

OLED (organic light emitting diode)

OLED displays organic compounds that emit light when an electric current is applied. It does not require a separate backlight, resulting in thinner displays with higher contrast ratios and better colour reproduction compared to LCD and LED displays.

OLED displays offer wide viewing angles and faster response times, making them suitable for high-end signage applications. However, OLED displays can be more expensive and may have issues with longevity compared to some other display technologies, particularly in high-brightness applications.

Flexible LED transparent screens can be directly attached to glass for installation, at widths as ultra-thin as 3mm ultra-thin design to play video, and at up to 90% transparent curved surfaces. This allows for immersive LED effects: sound and vibration functions and 360-degree vision. Some applications can even show content on both sides of the screen.

Micro LED

Micro LED is, like LED, an emissive display (not requiring a backlight) but doesn’t rely on organic compounds to make light. It is still at an early stage in tiled ultra-large sized TVs and wearable devices: due to cost it was announced that Apple would launch the first micro LED watch in 2027. 

LG Display recently announced the world’s first stretchable display, which can be deformed by as much as 20% of its original size and shape, at a resolution of 100ppi and full-colour RGB. Alongside its thin, lightweight design, the technology offers next-level versatility for various daily scenarios. Attachable to curved surfaces such as skin, clothing, furniture, automobiles and aircraft, this innovation expands the potential of the display in various industries, such as fashion, wearables, mobility and gaming.

Future applications could include stretchable screens integrated into furniture designs or wallpapers and curved 360° displays for use in advanced control systems in aeroplanes or cars. 

In summary, the main differences between LCD, LED, OLCD, and OLED in signage lie in their underlying technologies, with each offering unique advantages in terms of brightness, colour reproduction, viewing angles, energy efficiency, and form factor. The choice of technology depends on factors such as the specific application, budget, and desired features of the signage.

by FESPA Staff Back to News

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