Luminous efficacy

LUMEN PER WATT (lm/W). A unit of luminous efficacy. (The SI unit of luminous efficacy.)... 

The luminous efficacy or power efficiency is the lumen output p>er input electrical power of the device. It is measured in lumen per watt (hn/ W) or candela per ampere (cd/ A). It is represented by Jjp. In order to compete with the fluorescent lighting market, the efficiency of OLED sources should be 120 Im/ W or more. To meet the above requirement the OLED sources must have an electrical to optical pxjwer conversion effidency of 34%. For white light with a CRI of 90 the maximum value is 408 Im/W and for a CRI of 100 it is 240 Im/W (Kamtekar 2010). 

Scotopic and photopic curves for spectral luminous efficacy (after data published in Wyszechy and Stiles, 1982, p. 256). 

Fig. 1.1 History of luminous efficacy for incandescent, halogen, fluorescent, sodium-vapor lamps, and white LED. Adapted from Ref. [12] lOP Publishing. Reproduced with permission. All rights reserved...

Narukawa Y, Ichikawa M, Sanga D, Sano M, Mukai T (2010) White light emitting diodes with super-high luminous efficacy. J Phys D Appl Phys 43 354002. doi 10.1088/0022-3727/ 43/35/354002... 

SSL performance is characterized by the luminous efficacy (ifehnW ) that accoimts for the ratio between the luminous flux (Im) and the electric power (W), offering the following advantages, compared with conventional light somces [9,10] ... 

Figure 28.1 Evolution in the luminous efficacy of distinct light sources. The curves of incandescent, halogen, high-intensity discharge (HID) (including mercury vapor, metal halide, and sodium vapor lamps), and fluorescent lamps are adapted from Ref. [8]. The LED curve is built based on data reported by Kovac et al. [16] and Farinola and Ragni [13] and the...

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