Transflective Laptop Screens?

Ed_Moyse writes "It's a beautiful sunny day here in Geneva, and I've just been outside, enjoying a game of Advance Wars on my GBA. What I'd enjoy even more is to be able to work outside. Does anyone know why reflective laptop screens don't exist? It'd save battery life and should (if the GBA is any guide) work indoors too. Geeks with tans!" Timothy points out that what this reader is probably looking for is a transflective display, not a reflective display. The difference is that transflective laptops don't depend on ambient light, because they can be selectably backlit. Anyone who has ever used a laptop outside will know the advantages this may provide over your traditional LCD screen.

Comments

I suppose *someone* has to answer this...

[uslinux.net]

Too bad it's not me. I spent some time a while back on Seiko's website when I was looking into building an LCD for a home MP3 player. Transflective, FSTN backlit displays are the most expensive option. But the truth is, I don't know what most laptops use now (and I'd guess not many others do, either, or you would've already found your answer). I would guess current LCD panels are transmissive - they suck a LOT of power, but they look good in everything but sunlight.

In fact, from lxdinc.com: "A reflective display has the brightest appearance, with the highest contrast ratio possible. Unfortunately, it will be difficult to read at night or under changing lightning conditions. If your display must be readable under a wide range of lighting conditions, you will generally want a transflective display so that it will look very good in the bright sunlight, but will also be backlightable at twilight and at night. A transmissive display must always have a working backlight, and is therefore unacceptable in applications where power consumption is a problem.

The tradeoff with a transflective display is that it will not look as good as a reflective display during the day, and it will not look as good as a transmissive display at night. It will however enable you to have an acceptable compromise between the two, and provides a very acceptable appearance."

Palm 505

[E1v!$]

If you wonder why laptops aren't using these, go back to the review of the 505. Almost every review complained about the display quality/brightness. If laptop makers put these in their machines, they'd sell very few of them.

And honestly, have you ever tried coding in bright sunlight? I have a nice patio out front (in AZ). If it's windy and I've made (paper) notes they try to go all over. Suntan? Go on a major coding streak and you can call it sun-BURN!

(Still, I'd buy one if available)

There are many reasons...

[stienman]

Transflective displays are expensive, they can't gurantee color quality or brightness (since the light source is not defined except in total darkness), and the simple fact is that even in sunny conditions you have to orient yourself just right to have the sun do it's job in lighting up your diaplay. This is the same technology used in the IPAQ and the rest of the newer PDAs.

Manufacturer's of laptops have likely determined that the majority of customers use their laptops under a certian range of conditions, mostly indoors, and mostly under office lighting. Also, transflective displays cannot be backlit. The material used to take light from the side (from LEDs, CCFL tubes, etc), shine it over, through the LCD, and allow it to then pass back to the user are not only expensive to manufacture and handle (easy to scratch, must be worked with in clean room, etc) but lose a portion of their light, meaning less light for the display.

This makes them, overall, more expensive in both cost and energy usage.

As with all LCD parts it's not as much of an issue with smaller devices (PDA, game machines, phones, etc), but the cost in a laptop isn't worth it, especially for the very small percentage of users that would benefit from it.

-Adam