Edge LED backlight is going to minimize the number of LED and enhance illumination, light efficiency and light power.
It is going to be super-light and thin and low cost so that the light guide plate is going to be thinner, and the illumination area of LED is going to be smaller.
Light guide plate is becoming long and narrow, and the number of LED lamps is decreasing, so that LED backlight is decreasing light-emitting angle to enhance the light efficiency in the narrow side, and it is also increasing the light-emitting angle to decrease shadow between LED lamps in the long side.
Bottom LED backlight is going to be thinner and lower cost so that the number of LED lamps is decreasing and light-emitting angle is increasing from 120 degrees to 160-170 degrees.
So far, the main solution is that using two times optical lens which is high cost and low light efficiency.