In 1999, Roland Haitz plotted a graph that showed the remarkable exponential progress of LED technology over the previous 30 years. The data he gathered from his employer, Palo Alto, California, headquartered technology giant Hewlett Packard, has become enshrined in 'Haitz's Law'. That's because it showed cost per lumen falling by a factor of ten each decade, and the luminous flux per LED package increasing by a factor of 20 over the same time.
What's even more remarkable is that this exponential growth has accelerated yet more since Haitz described it. But when something becomes a 'law' it can be easy to forget that delivering the improvements it details remains a technical challenge. And while solid-state technology is unmatched for illumination efficiency, increasing LED output still demands raising overall power ratings and dissipating the heat that results. Doing this while further increasing lm/$ puts the burden squarely on LED packaging, and particularly the substrates that LED chips are mounted on.
