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View Full Version : laptops outdoors


gandalf55
Jul 6, 2003, 08:45 AM
when and how might we get a laptop screen which is actually viewable when outside? shade works but if there is a decent amount of light on the screen, it's basically unusable. what would it take to get this to work better?

or is it beyond reality since i would think the screen would have to adjust somehow (either MUCH brighter) or perhaps a screen on the display which could somehow filter the light down?

iGav
Jul 6, 2003, 09:32 AM
It's not really just laptops that suffer this.... TV's do as well, also LED's etc etc..

I can't really see a way that they can make it X times brighter to combat the glare, increasing the brightness would increase battery drain, and increase heat output etc etc.... and even then I don't think the technology exists to achieve this...

It would be great if it happened though... I used to be a freqent visitor to Brighton Beach with my PowerBook!! :D

rainman::|:|
Jul 6, 2003, 10:44 AM
yeah, you have no idea how strong the ambient lighting outside is-- it's a wonder we can see screens at all. There's no way to increase the brightness that much. OLED displays might provide a little better picture but I doubt that helps much either...

pnw

DHagan4755
Jul 6, 2003, 11:00 AM
I'm not an expert in this area, but outdoor light is far brighter than a laptop's backlight. Light sources are measured using the Kelvin scale.

http://www.cameraguild.com/technology/images/FlourescentsB.jpg

I would say a laptop's screen falls in the 4000-4500K range since they have this yellowish look to them outside. I think if laptop screens got any brighter they would be unhealthful for your vision.

Daveman Deluxe
Jul 6, 2003, 11:14 AM
The thing that I don't understand is back when I had a PowerBook 520, I could turn backlighting OFF when I had direct sunlight at my back. Now that I have my iBook, I can barely use it outside at all. What's up with that?

LethalWolfe
Jul 6, 2003, 11:51 AM
Originally posted by DHagan4755
I'm not an expert in this area, but outdoor light is far brighter than a laptop's backlight. Light sources are measured using the Kelvin scale.

http://www.cameraguild.com/technology/images/FlourescentsB.jpg

I would say a laptop's screen falls in the 4000-4500K range since they have this yellowish look to them outside. I think if laptop screens got any brighter they would be unhealthful for your vision.

The Kelvin scale you posted measures the color of light, aka its color tempature. It doesn't refer to how bright the light is.


Lethal

EDIT: Also you can adjust the color temp of your display (at least on desktops you can I'd assume you can laptops too) so that it matches the color temp of the environment you are in. This would solve the 'yellowish look" you mentioned. Of course if you set your screen to look "normal" when compared to sunlight it will look bluish when viewed indoors under incandescent<sp?> lights.

janey
Jul 6, 2003, 01:36 PM
that's one major problem that i despise...i really can't wait until laptops with OLED screens come out.

XnavxeMiyyep
Jul 6, 2003, 02:03 PM
In various editions of MacHome, I've seen ads for shades you put over the top of the Powerbook so you can see the screen. I have no idea whether they actually work, as I have never used one.

BigJayhawk
Jul 6, 2003, 02:20 PM
The major reason that screens do not work in bright light (as I understand it) is that they use a backlighting themself to display the images on the screen. This is done by BLOCKING the backlighting in certain ways. So, if the backlighting is overpowered by the frontlighting they simply wash each other out. As long as we have displays that work by BLOCKING their own backlighting, this should still be an issue.

In comes OLED. OLED actually has NO BACKLIGHT and CREATES ITS OWN LIGHTING. Therefore, (once again, as I understand it) they will even be able to put up BILLBOARDS that work in bright light and no light just as well as anything available today (for EITHER condition). Also, since it is thinner than a human hair (although it must be mounted between a protective material that is not quite as thin), the angle of visibility will be virtually 180 degrees!

Oh, can we dream, can we dream?

Daveman Deluxe
Jul 6, 2003, 02:53 PM
Jay-

With an LCD, there is a layer of liquid crystals sandwiched between two layers of transistors. A protective glass or polycarbonate plate covers the whole thing. Behind all of this is a reflective layer.

When an electric current is applied to the liquid crystal, the liquid crystal in that pixel uncoils, allowing light to reflect off of the reflective backing. In low-light situations, that light must be provided by backlights, which are thin cathode tubes (not unlike a fluorescent light) mounted, typically, on the sides and the top of the screen, out of view. Their light reflects off the back of the screen and out of any pixel in which the liquid crystal is uncoiled.

It used to be (as in my PowerBook 520) that if you sat with the sun at your back, the sunlight would work as effectively as the backlighting. It entered the screen and reflected off the reflective layer where crystals were uncoiled. Nowdays, however, that cannot take place. When you sit outside, the pupils of your eyes "stop down", so to speak. Since the backlights in the LCD are much dimmer than the ambient light from the sun, it cannot possibly compete in terms of brightness with the ambient light and so it is difficult to see.

In earlier LCDs, the sun itself could provide the light to reflect and so the brightness <i>could</i> keep up with ambient light--they came from the same source-the sun!

My guess is that somehow ambient light can no longer enter the LCD from the front. I have no idea why.

Abstract
Jul 6, 2003, 05:37 PM
I didn't read the entire thread (too lazy :D), but the reason it is difficult to see the screen is because of the reflection off the screen. The screen covers that were mentioned basically reduce the amount of glare/reflection from the screen, while allowing all the light coming from the display to pass through this transparent cover.

Kwyjibo
Jul 6, 2003, 06:58 PM
yeah....i hate than i have to ifnnd a shady spot or wait until the evening to use my ibook on my hammock