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Comment by culopatin | Hacker News Reader

After seeing how the translucent Apple logo on some MacBooks let the sun in through the back of the screen, I always wondered why no one made a translucent screen backing so you could put the back of the laptop against the sun and get more light in

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One of the biggest reasons LCDs are so inefficient is that they block most of the light. Each R/G/B subpixel blocks everything that isn't that colour and turns it into heat. The polarizer also has to block all the light that is the wrong polarization and turn that into heat.

This means that the backlight has to be incredibly bright relative ambient light. So even if you positioned it to harness the power of the sun as a backlight, it'd be a lot dimmer than the ambient sunlight.

The reflective LCD in the OP is nice because the sun is behind you instead of shining in your face.

TL;DR, you'd end up having to squint your eyes anyway since the display would be much dimmer than the sun you're staring at, unless you rigged up some cardboard so you didn't have to stare into the sun.

Transparent LCD display used to be commonly available for use with overhead projectors. Back in the 80s and 90s, "every" classroom had these projectors to put transparencies on, or just to write on with a dry erase pen. So, put together a transparent LCD screen to go on top and boom, LCD projector for your computer. Of course, integrating the bulb, the LCD, and the optics happened shortly after (with much smaller LCDs) with nicer output, but less flexibility.

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