LEDs for Solid-State Lighting: State of the Art and Challenges

LEDs for Solid-State Lighting: State of the Art and Challenges

Muhammad Wasif Umar (Universiti Teknologi PETRONAS, Malaysia) and NorZaihar Yahaya (Universiti Teknologi PETRONAS, Malaysia)
DOI: 10.4018/978-1-7998-0117-7.ch011


Solid-state lighting technology is rapidly gaining acceptance in lighting industry street lighting, traffic lighting, decorative lighting, projection displays, display backlighting, automotive lighting, and so on. Differing from conventional light sources that use tungsten filament, plasma, or gases to generate light, solid-state lighting is based on organic or inorganic light emitting diodes (LEDs), and has the potential to generate light with almost 100 % efficiency. LED luminaires have a long lifetime and are environmentally friendly with no toxic mercury contained. However, the success of these luminaires depends on system design, which comprises an understanding of several factors such as performance and control. In this chapter, we shall touch upon some technological advancements in the field of solid-state lighting technologies and challenges that limit their market penetration for consumer lighting.
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Light emitting diode (LED) based solid-state lighting (SSL) solutions have made tremendous progress over the last several years, with the potential to make much more over the coming years. The four major factors supporting their popularity are: energy efficiency, long lifetime, mercury free structure and design flexibility. Since the origin of first red LED in 1962, the technology has grown rapidly. In the 1970s and 1980s seven-segment LED displays were in widespread but falling off due to liquid crystal displays with their lower power consumption and greater display flexibility at the time, for a while it seemed like LEDs would not be a popular technology. Due to defects in crystal structure and poor substrate creation, the light outputs of LEDs were not anywhere near its potential. However, in the 1990s high-brightness gallium nitride (GaN) LEDs were discovered and it was a short step to the 2000s, when bright white LEDs became a lighting revolution (Bender, Marchesan, & Alonso, 2015).

LED application areas include LCD backlights, displays, transportation equipment lighting and general lighting (see Table 1). LEDs are used as a light source for LCD backlights in products such as TVs, mobile phones, monitors and cameras (Ahn, Hong, & Kwon, 2016; Moon & Oh, 2015). Display applications include outdoor billboards, electronic scoreboards and signage lighting (e.g., LED strips and lighting bars). Examples of transportation equipment lighting areas are passenger vehicle/train lighting (e.g., meter backlights, tail and brake lights) and ship/airplane lighting (e.g., flight control and searchlights) (Long et al., 2015). General lighting applications are divided into indoor lighting (e.g., LED lighting bulbs, surface and desk lighting), outdoor lighting (e.g., street lighting, decorative lighting and flood lighting) and special lighting (e.g., appliances and elevator lighting) (Bender et al., 2015). LED-based light sources (lamps, modules) and luminaires for general lighting are rapidly gaining acceptance with a growing list of applications, such as, street lighting, commercial/business lighting and consumer applications. In this chapter, we will focus on some of recent technological developments in the field of SSL technologies for consumer lighting applications and challenges that limit their market penetration.

Table 1.
Application areas of LEDs
LCD backlighting     • TVs
     • Mobile phone
     • Monitors
     • Cameras
Displays     • Billboards
     • Electric scoreboards
     • Signage lighting
Transportation     • Vehicle/Train lighting
     • Ships/Airplane lighting
General lighting     • Indoor lighting
     • Outdoor lighting
     • Special lighting

Barriers To Adoption

In previous section, a few key historical advancements and profound energy, economic, performance and application benefits of the LED technology has been mentioned. However, in spite of the numerous advantages, LEDs have their set of challenges as well, which have been holding back their market growth to an extent. The following lists some of the technical and market barriers to LED technology. Overcoming these barriers is essential to their rapid market deployment.

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