Front light

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showing the E Ink stack with front light

E Ink displays can be used in applications or environments with little or no external light source through the integration of a front light solution. Of course they can also be used with a normal book light.

Contents

[edit] Overview

The E Ink display reflects the ambient light on the display to provide a reading environment. This means that it cannot be backlit which means that low light situations can make reading difficult. One solution is to use a book light as would be used on a regular paper book. A second solution is to provide some sort of builtin or add-on front light.

A front light use a very thin light guide material to uniformly disperse light over the entire display. The light source is usually in the form of LEDs mounted in the sides of the display module. E Ink can manufacture the entire display module including the front light.

[edit] History

The Sony PRS700 was the first E Ink device to feature a front light. It featured two levels of front light. Some users felt the light made the screen display fuzzy. The light was an additional overlay that could be placed over the screen.

Today the front light is built into the display itself. Both E Ink Pearl and E Ink Carta can support a front light. The color display E Ink Triton can also be front lit.

[edit] Issues

In general most people enjoy the ability to turn on the front light when needed. Some people have reported some issues with some devices.

  • Some believe the light screen, when off, causes a less clear display
  • Some do not like the color imparted to the screen on some devices, too yellow.
  • Some screens do not have a uniform light display across the entire display. This may vary with the brightness.
    • This depends largely on how many LED's are available on the device. Common values are 4 to 10.
    • The larger the display the more difficult it is to get an even light. Currently the largest devices that support a front light are 9.7".
  • For some the lowest light setting on some devices is too bright for night time reading.
  • If you have the opportunity it is best to try out the screen light before purchasing.
  • Some users complain of Blue-light exposure. This is specifically addressed in some devices.

[edit] eBook Applications

These are 6" screen devices unless otherwise marked. Listed in alphabetical order.

use Special:WhatLinksHere/Front_light to see what pages refer to this one.

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