Haitz's law is an observation and forecast about the steady improvement, over many years, of

light-emitting diode A light-emitting diode (LED) is a semiconductor device that emits light when current flows through it. Electrons in the semiconductor recombine with electron holes, releasing energy in the form of photons. The color of the light (cor ...

s (LEDs). It claims that every decade, the cost per lumen (unit of useful light emitted) falls by a factor of 10, and the amount of light generated per LED package increases by a factor of 20, for a given wavelength (color) of light. It is considered the LED counterpart to

Moore's law Moore's law is the observation that the number of transistors in a dense integrated circuit (IC) doubles about every two years. Moore's law is an observation and projection of a historical trend. Rather than a law of physics, it is an empir ...

, which states that the number of transistors in a given integrated circuit doubles every 18 to 24 months. Both laws rely on the

process optimization Process optimization is the discipline of adjusting a process so as to optimize (make the best or most effective use of) some specified set of parameters without violating some constraint. The most common goals are minimizing cost and maximizing ...

of the production of

semiconductor device A semiconductor device is an electronic component that relies on the electronic properties of a semiconductor material (primarily silicon, germanium, and gallium arsenide, as well as organic semiconductors) for its function. Its conductivity li ...

s. Haitz's law is named after

Roland Haitz Roland (; frk, *Hrōþiland; lat-med, Hruodlandus or ''Rotholandus''; it, Orlando or ''Rolando''; died 15 August 778) was a Frankish military leader under Charlemagne who became one of the principal figures in the literary cycle known as the ...

(1935–2015), a scientist at

Agilent Technologies Agilent Technologies, Inc. is an American life sciences company that provides instruments, software, services, and consumables for the entire laboratory workflow. Its global headquarters is located in Santa Clara, California. Agilent was establi ...

among others. It was first presented to the larger public at Strategies in Light 2000, the first of a series of annual conferences organized by Strategies Unlimited. Besides the forecast of exponential development of cost per lumen and amount of light per package, the publication also forecast that the

luminous efficacy Luminous efficacy is a measure of how well a light source produces visible light. It is the ratio of luminous flux to power, measured in lumens per watt in the International System of Units (SI). Depending on context, the power can be either the ...

of LED-based lighting could reach 200 lm/W ( lumen per Watt) in 2020, crossing 100 lm/W in 2010. This would be the case if enough industrial and government resources were spent for research on LED-lighting. More than 50% of the electricity consumption for lighting (20% of the totally consumed electrical energy) would be saved reaching 200 lm/W. This prospect and other stepping-stone applications of LEDs (e.g. mobile phone flash and LCD-backlighting) led to a massive investment in LED-research so that the LED efficacy did indeed cross 100 lm/W in 2010. If this trend continues, LEDs will become the most efficient light source by 2020. The theoretical maximum for truncated blackbody white light source (at 5800K colour temperature with wavelengths restricted to the visible band of between 400nm and 700nm) is 251 lm/W. However, some "white" LEDs have achieved efficacies of over 300 lm/W. In 2010,

Cree Inc. Wolfspeed, Inc. is an American developer and manufacturer of wide bandgap semiconductors, focused on silicon carbide and gallium nitride materials and devices for power and radio frequency applications such as transportation, power supplies, powe ...

, developed and marketed the XM-L LED that claimed 1000 lumens at 100 lm/W efficacy and 160 lm/W at 350 mA and 150 lm/W at 700 mA. They also claimed to have broken the 200 lm/W barrier in R&D with a prototype producing 208 lm at 350 mA. In May 2011, Cree announced another prototype with 231 lm/W efficacy at 350 mA. In March 2014, Cree announced another prototype with a record-breaking 303 lm/W efficacy at 350 mA. In 2017,

Philips Koninklijke Philips N.V. (), commonly shortened to Philips, is a Dutch multinational conglomerate corporation that was founded in Eindhoven in 1891. Since 1997, it has been mostly headquartered in Amsterdam, though the Benelux headquarters i ...

Lighting started offering consumer LED lights with 200 lm/W efficacy in Dubai using LED filament technology, three years before what Haitz's law predicted.

References

External links

* {{DEFAULTSORT:Haitz's law Computer architecture statements Lighting Light-emitting diodes Rules of thumb Semiconductor devices