For another thing, LEDs have become much more efficient. So, where early products failed, many of today’s LEDs do not necessarily need a heat sink, unless they are high-power models. Many chip sets that have proven successful even in the sign industry can be mounted on almost any type of material without worry of failure.
To keep on the safe side, some categories of LEDs are now provided to the sign industry mounted on metal-core boards. This is like starting with a built-in heat sink.
As LEDs have become less heat-sensitive, the emphasis of engineering has switched to focus on drivers and power supplies. These systems almost always have heat-sensitive electrolytic capacitors that can fail. As such, they have become the new weak point in a sign system.
With the undesirable consequence of LED drivers becoming the components that determine how long an LED will last, the industry’s focus will need to expand to improve their performance. On the testing and measurement side, for example, there is currently a lot of effort being put into standardization, to make LED manufacturers’ claims of longevity more believable.
Also, as the installed base of LED systems increases, more emphasis is being put on their power-factor characteristics and low total harmonic distortion (THD).
Motivating factors
Standardization may not be appropriate for LEDs themselves, however, outside of general illumination applications. This is because, for the most part, every sign is different and unusual. There is still a great degree of artistry and craftsmanship in the industry, rather than a one-size-fits-all approach.
Also, additional efforts to cut energy consumption are still not as major a decision factor in the sign industry as they are elsewhere. Instead, the adoption of LEDs has been motivated by efforts to reduce costs, e.g. by using fewer drivers and needing less frequent maintenance. Improved efficiency is a secondary ramification compared to cost-effectiveness.
George Preston is CEO of Permlight, which designs and manufactures light engines for LED systems for signage and other markets. For more information, visit www.permlightforsigns.com.
