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How to make screens visible in daylight

  1. Mar 30, 2013 #1
    I was just using my phone outside on the first beautiful sunny spring day of the year, when I noticed that I couldn't see my screen at all. I thought about what was happening. My screen, when off, is dark grey/black, and its made up of pixels that can change their colour independently. Since light is additive, when the sun is shining on my screen, it does a great job of lighting up the totality of my phone, and yet we still try to combat it using backlights. The backlights in my phone are certainly not bright enough (even on full brightness) to even slightly compete with the sun. All I saw was the natural colour of my screen: black.
    Why can I see the rest of the physical world so well? Because these are not trying to compete with the sun, instead they work with it. Being secondary light sources, they just reflect a small portion of the energy radiated by the sun and they become perfectly visible! Why can't screens do just that?

    I know I'm going on a bit of a rant here but I'll get to my point shortly.

    Certain fish and other deep sea creatures have the ability to take white light and reflect it back as various colours. They can even change the wavelength of light they reflect and end up making mesmerizing colour patterns that attract prey. They don't create light, they reflect it, and that would make them perfectly visible in daylight. Why can't our screen be made of these bio-materials?

    I think screens made to selectively reflect ambient light would be much more useful in everyday life. They wouldn't give people vision problems/headaches. Staring at a light producing screen hurts one's eyes, but a secondary light source screen would blend into the environment very well.

    I'm sure I'm not even close to being the first person to think of this, and I'm not proposing a method of doing it because I have no knowledge of the subject.
    I just wanted to pitch an idea and maybe start a discussion.

    Thanks for reading.

    Simon
     
  2. jcsd
  3. Mar 30, 2013 #2

    mfb

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    There are screens which can, but they have long switching times. And as you can imagine, they are problematic without external light sources. Shielding the sun is usually possible, creating one is problematic.
     
  4. Mar 30, 2013 #3

    sophiecentaur

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    I think you are referring to 'e-ink' technology - like the screens on Kindles etc. They work on reflected light and are fine in the brightest sunlight. They work a bit like the Xerox process, with black particles that are moved by a brief pulse of energy ant then stay there for ever or until they are cleared by another pulse of energy. Great for battery life. Also, hopeless in the dark, so some displays have a backlight, as in LCD displays.

    I believe there are some experimental three colour e-ink systems but I don't think that there is anything on the market yet.
     
  5. Mar 30, 2013 #4

    cjl

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  6. Mar 31, 2013 #5

    CWatters

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    Most panels are "transmissive" and use a backlight. What happens in sunlight is that your eyes "stop down" to compensate for the high light levels. The LCD therefore appears a lot dimmer. You could solve it by turning up the brightness but that causes battery life and other issues.

    Some panels are "reflective". They have a mirror instead of a backlight. They get brighter in sunlight but are harder to see indoors in poor lighting.

    Some panels are "transflective": They are a combination of both.
     
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