yeah basically they tested the idea by taking and LCD panel and shining a projector through it with the same image. The projector image therefore had light where light was needed and in the same colour.
Obviously that is not practical for a tv in a house so the next step was an array of RGB leds which basically have the same image but very pixelated - a bit like one of those giant LED screens at concerts. The backlighting therefore reinforces the image on the LCD and gives you the high dynamic contrast which can be many times greater than the lcd panels contrast ratio.
Edge lit LED technology basically replaces the edge lit CCFL lighting with LED ones. You need to use edge lit to disperse light evenly as you can't just dump a couple of bright leds behind the lcd. There is a special light guide layer of acrylic with different sized dimples which spread out the light almost evenly across the surface. Then they use some diffuser and polarising layers between the light guide and the lcd.
All these layers and light pipe reduce the light considerably, but the lcd itself is the biggest intensity loss. Direct backlighting needs much more initial technology and expense but can be much more efficient as you are not wasting light and gives better contrast and can give a brighter image for the same overall average power consumption.
(I spent a lot of time working on daylight viewable LCD screens for in car use before LEDs hit mainstream TVs).