LED filament bulbs have really taken off over the last few years. I ignored the older ones as decorative curiosities, but the current household ones in Warm White and Cool White from Osram can top 130 lumens /Watt. They run dramatically cooler than non-filament bulbs.
This is because there are several LEDS in series in each filament, which allows a higher drive voltage and a more efficient driver design. Typical designs have 4 filaments of 20-odd LEDs each, so each LED in a 7W bulb uses approximately 80mW.
A new video from BigClive caught my attention:
The
Dubai Lamp bulbs are available only in the UAE under an exclusive deal. By tripling the number of LEDs (12 filaments), Philips was able to reduce the power of each LED to only 10mW, which improved efficacy to a very impressive 200 lumens per Watt. The reduced LED heating means that the bulbs should last a lot longer - Philips claims 25000 hours but surely you're now limited by the longevity of the driver rather than the LEDs?
In other words, Philips just boosted their luminous efficacy and longevity by 65-100%, without introducing any new technology, because someone gave them an incentive.