Front light

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.

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 for select sizes.

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. Front lit devices began appearing in the fall of 2012. Both E Ink Pearl and E Ink Carta can support a front light. The color display E Ink Triton can also be front lit. E Ink Mobius has a flexible substrate for the TFT display making it nearly unbreakable. A fully flexible display cannot be front lit but it is possible to place a glass surface in front of the display and use it for the front light. This would allow the screen to be broken but it is the substrate that is most likely to break as the front display can use a reinforced glass reducing this risk.

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 from E Ink that offer a front light are 9.7". However this is solved for some Boyue 10.3" devices.
• 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.

E Ink front lights

The following sizes are available from E Ink and can be purchased with a front light.

• 3.84" 600 x 600 pixels, 69 x 69 mm, 220 ppi, Carta 1.2, Glass
• 6" 1072 x 1448 pixels, 90.60 x 122.40 mm. 300 ppi, Carta 1.2, Glass
• 6" 1024 x 758 pixels, 90.60 x 122.40 mm, 212 ppi, Carta 1.2, Glass
• 6.8" 1440 x 1080 pixels, 103.68 x 138.24 mm, 260 ppi, Carta 1.2, Glass
• 7" 1680 x 1260 pixels, 142 x 107 mm, 300 ppi Carta 1.2
• 7.8" 1872 x 1404 pixels 158.5 x 119 mm, 300 ppi Carta 1.2
• 8" 1920 x 1440 pixels 163 x 122 mm, 300 ppi, Carta 1.2
• 9.7" 1200 x 825 pixels, 203 x 140 mm, 150 ppi, Pearl, Glass, no long available. Carta available at this resolution.

Other devices

Some 10.3" devices from Boyue have front lights, which is a custom addon to the E Ink display. They are both 1872 × 1404 pixel 227 ppi using E Ink Mobius Carta display.

• BOYUE Likebook Note
• BOYUE Likebook Mimas

The only 13.3" unit device with a front light is from Onyx

• BOOX Max Lumi: 2200 x 1650 pixels, 207ppi, 4:3 aspect ratio, contrast 15:1

eBook Applications

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

• BOOX C65‎‎ Afterglow
• BOOX E43 4.3" device
• Boox T68‎‎ 6.8" device
• Boox N96ML 9.7" device, currently largest screen available from E Ink with a frontlight.
• Boyue T61
• BOYUE Likebook Note 10.3" the largest currently available with a frontlight
• Cybook Odyssey HD FrontLight
• Cybook Ocean 8" device
• ICARUS Illumina Pro 9.7"
• Kindle paperwhite both 1 and 2, 4 LEDs
• Kindle Voyage 6 LED's
• Kindle Oasis 10 LED's
• Kobo Aura - Comfortlight
• Kobo Glo
• Kobo Aura HD‎ - Comfortlight 6.8" device
• Kobo Aura H2O - Comfortlight 6.8" device
• Nook touch with glow light™
• NOOK glowlight
• Nook GlowLight Plus
• PocketBook Color Lux‎‎ 8" screen and Color display.
• PocketBook InkPad 8" device
• PocketBook Touch Lux - Pearl display
• PocketBook Touch Lux 3 - Carta display
• PocketBook Ultra

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