Power saving is the biggest challenge of today's appliances viz TVs, Laptops, Tablets and Smart Phones etc, both by AC and DC battery sources. I shall consider only the TV, while the technique could as well be adopted for rest of the appliances. TVs consume 3 to 8% of global electricity. Tougher regulations continue to reduce the maximum power that a new TV can consume, e.g. the current maximum for any size screen is 85 Watt by Energy Star.
Consumption can be brought down considerably by advance techniques viz LED backlighting. Since LED backlighting power ranges from 30% to 70% of overall system power in LCD TVs, improvements in the efficiency of the backlighting power circuit can make a considerable contribution to system efficiency. Backlighting can be achieved by two different techniques viz 1) Direct and 2) Edge Lit. Both techniques have their pros and cons. In direct backlit, the LEDs are directly under the LCD, causing low power, good thermal design and excellent scalability with virtually no limit to the screen size. Panels tend to be thicker than edge lit versions, but with latest light distribution techniques, sizes as thin as 8 mm can now be achieved . Direct backlighting enables sophisticated local dimming, which lowers power consumption and increases the dynamic contrast ratio. In edge lit backlighting, the LEDs are at the edges of the screen. A light guide applies the light smoothly to the display. This can be done with good optical uniformity in screen sizes up to 60", and enables backlighting units with thickness of just 5 to10 mm.
LED backlighting uses several Energy saving methodologies:
1) Architecture for an LED backlit driver system
2) Single String and Single DC-DC Converter
3) Multi-string with single DC-DC converter
4) Multi string mixed architecture
5) Regulating current to match the characteristics of LEDs
6) Current sink characteristics
7) Feedback regulation for power optimization
8) Smart dimming for edge-lit systems
9) Ambient light sensors
10) Motion/Camera assisted brightness control
My idea is to marry two i.e Direct and Edge Lit backlighting, keeping Edge Lit technique intact, while modifying Direct backlighting from active to passive means by using luminescent
chemicals, specially Strontium Aluminate in particular branded Super-LumiNova (Note: tritium-powered light source may also be used but it is radio active with half life of over 12 years) for painting back of the LCD panel to make it a reflector of ambient light and light from edge LEDs. In this way, light guide of the edge lit LEDs will only apply light for a very reduced period of time and the glow of the chemical shall illuminate the screen, thereby achieving drastic improvement in power savings. There may be added a black & white LCD shutter in between chemical coated back panel and front LCD to isolate the chemical coated backlit panel whenever edge lit only operation is required. The chemical may be custom modified for this particular purpose for achieving maximum efficiency.