LED and AMOLED screens are admired by screen junkies all over the word because they produce the deepest blacks in a mobile device display. This is because LED screens, including Samsung’s more preferred AMOLED screens, just basically turn off when they’re assigned to draw the “black” color. That’s what the new app “Pixel OFF” tries to do, because theoretically, LED pixels not emitting light draws no electrical power.
So, in theory, an LED or AMOLED screen with more black draws less power than those that show more color. That is where Pixel OFF tries to help you save battery power – it overlays a layer of evenly-spaced black pixels on your screen, theoretically lowering the display’s power consumption, thereby saving the user battery life.
Mind you, on LED and AMOLED screens can benefit from this, if ever. LCD screens can’t claim the same benefit because of a different way of “drawing” the black color on screen. The app has received some good feedback, and it requires no root at all, so it’s an easy install. Our question is, what is the difference between applying the app and say, just manually lowering brightness?
The app is free to pick up at the Google Play Store (source link below), but it has an IAP that allows you to unlock more noticeable or less noticeable overlays. You can also set the app to trigger when your battery reaches a certain level. Our suggestion is this – study the app’s capabilities and tell us about it.
DOWNLOAD: Google Play Store
VIA: Android Police
I remember when this app, or one quite like it in principle came out many months ago. The developer seemed clueless about how regular LCD screens worked. At least, this article gets the basics right.
In an LCD screen, all the light comes from the backlight, which is white. Each pixel consists of (typically three) sub-pixels. Each of those is a “light valve” that lets more or less back light pass to the viewer. As well, each of those three has its own color filter, one each being red, green, or blue. Your lead microphoto shows the sub-pixels very well.
Otoh, AMOLED and other LED screens have no backlight, and their sub-pixels emit primary-colored light.
Unless you’re wearing sunglasses, you wouldn’t notice, but LCD screen light is polarized, because those wee light valves are dimmers that work by using polarized light, like the polarizing dimmers for binoculars and maybe adjustable camera filters. In such dimmers, you have two polarizers, and one rotates a quarter turn.
In an LCD, the liquid crystal in each sub-pdxel does the rotating, more or less, according to the needed brightness. There are two full-screen polarizing layers, one between the back light and the LCD and color filter layers, and one in front of it.
[AMO]LED displays are much simpler!
In either type, dimming the display with the firmware brightness control does save power. Backlights use quite a lot.
Sorry, but this app seems more like a gimmick. Some people will unfortunately install it into devices that have LCDs, more than likely.
It would be kind if the developer puts up a message telling that this.app works only in [AMO]LED devices, and then checks whether the device is that type, and notifies the user. Unfortunately, it /appears/ to work in all types of displays.