In what state is the screen using the least energy, and where does it waste most of its energy.
In general there are three types of screens,
1CRT,
2LCD (Led, CCFL [Baklight]),
3OLED (PMOLED, AMOLED, Super AMOLED)
CRT retired not going to write about consumes the most energy compared to others horrible resolution,
LCD stands for Liquid Crystal Display the lcd responsibilityto is produce the colors when its not charges (No Voltage) it's transparent when it's fully charged it's opaque (Black) if there would be no backlight you would see black on black (Deep black) And red on black there fore there's a backlight that lights up the back of the lcd so you can actuly see the color of the lcd (Every pixel has 3 subpixels one for red one for green and one for blue [R,G,B])
LCD the most energy consuming is the back light, the rest goes for the LCD when the screen is black the backlight is the same bright as it always would Plus it has to charge both electrodes (Vertical + Horizontal) to block the Backlight.
There are two choices of backlight source one is CCFL fluorescent And LED, Led is obviously more efficient.
Color White is more efficient since it essentially means transparent it doesnt have to charge those pixels.
LCD screens cant produce true (Deep) Black since it has a backlight shining from behind it, therefore dynamic contrast ratio came into play it would dim the backlight of a particular section of the screen if there's no color needed in that section LCD = Black, Backlight = Black(Dim) you got true black color.
for screens that have a dynamic contrast ratio having a black background might save some energy.
Summary LCD to save energy
- Led Backlight
- lower the brightness as much posible,
- depending on your screen type white/black background, (native contrast ratio white background, dynamic contrast ratio Black Background)
OLED organic light-emitting diode, to be continued........
Instead of making light by heating a wire filament till it glows white hot (which is how a normal lamp works),An OLED is simply an LED where the light is produced ("emitted") by organic molecules, Organic molecules are simply ones based around lines or rings of carbon atoms, including such common things as sugar, gasoline, alcohol, wood, and plastics.
I don't want to get to technical, the bottom line is that oled screen doesnt need a backlight every pixel can produce light therefore to produce a black color the pixel and its subset are off and you get a deep true black and there's no energy used for those pixels, OLEDs use power as a function of the specific image being displayed. Dark images consume small amounts of power while light or white images consume maximum power, if you noticed the recent android battery saver mode set a black background to save energy,
Summary