-1
\$\begingroup\$

I just realized that the display on my 2012 Macbook Air is transparent. I had the screen brightness of the built in display on the lowest (off) while using an external monitor, and the sun came shining in on the back of the laptop, lighting up the "apple logo" part of the display - and I realized that I could see my desktop background there!

The picture was actually quite clear and had proper colors and everything. This led me to think that if somebody wanted to, they could create a transparent display by just putting clear glass or plastic behind it instead of black plastic or aluminium. I'm sure that with some engineering, some sort of solution that simply reflects sunlight or ambient light onto the back of the display could be constructed.

Of course it should be combined with a cover of some sort so that you can use it as a traditional display as well, but when out and about and on battery, it could be useful to be able to turn off the background light on the display and use it.

Given that people want their laptops and smartphones to have limitless battery life, how come this is not a thing? Is it mostly aesthetics? Or are there actual technical problems doing this? If my 6 year old laptop can do it, it can't be that difficult, right?

EDIT

To clarify, I'm not asking why manufacturers don't sell laptops with see-through displays or heads-up-displays. I'm asking why they're not inventing some clever way to utilize the ambient light when possible and desirable. It could be as simple as a fold-down back cover on the display, which could reflect sunlight into the display if folded down or just act as a normal display back cover when folded up. If I'm out in the sun with my laptop running low on battery, wouldn't it make sense to use free ambient backlight instead of wasting battery life on illuminating the display?

\$\endgroup\$

closed as primarily opinion-based by Chris Stratton, Elliot Alderson, RoyC, Dmitry Grigoryev, Finbarr Oct 26 '18 at 9:54

Many good questions generate some degree of opinion based on expert experience, but answers to this question will tend to be almost entirely based on opinions, rather than facts, references, or specific expertise. If this question can be reworded to fit the rules in the help center, please edit the question.

  • 1
    \$\begingroup\$ You lose screen brightness and everyone else can see your monitor. Pretty big drawbacks \$\endgroup\$ – MIL-SPEC Oct 19 '18 at 9:24
  • \$\begingroup\$ And, all the junk behind your screen now obscures what's on the screen. If reflections of lights are annoying, try reading a text that is splattered over a bunch of trees, a concrete parking lot, the cars driving around, and the people walking through the office. \$\endgroup\$ – JRE Oct 19 '18 at 9:29
  • \$\begingroup\$ Also consider what happens when your wife/girlfriend spots you surfing pornhub through the backside of the screen. \$\endgroup\$ – JRE Oct 19 '18 at 9:30
  • 2
    \$\begingroup\$ Not difficult, just not useful. Why in the sam hill would you want to see through the screen? Why would you want people to see what you are viewing (backwards.) \$\endgroup\$ – JRE Oct 19 '18 at 9:32
  • \$\begingroup\$ There was I think one laptop planned with a screen suitable for an overhead projector. You would still want a diffuser behind the laptop so privacy and distraction are not a big issue. The back light flap could also have solar cells to charge the battery when it is in the sun and using solar back lighting. I like the idea in a Mad Max world kind of way. \$\endgroup\$ – KalleMP Oct 19 '18 at 16:43
3
\$\begingroup\$

F18 HUD

Consider this transparent display: an F18 Head Up Display.

This display has a much simpler job than a laptop display - it must display monochrome symbology at a low framerate. It faces many of the same challenges however, as it must deal with unwanted light and object from behind the display obscuring the symbology, reflections from the front of the display and general brightness issues.

To combat the sunlight, the image must be projected from a high-brightness CRT, the kind found in old TVs, as digital projectors are only just becoming bright enough to use. To combat the reflections, the display must be angled downwards at 45degrees and the user (pilot) must not move too far either side, up or down as the viewing angle is extremely poor (15 degrees all round).

If the display didn't have to be transparent, all of this could all be fixed by using backing like the kind found on a laptop - which is significantly cheaper as LCD can be used.

\$\endgroup\$
2
\$\begingroup\$

What you are describing is a reflective screen (well of course you are not describing that, but that is the practical option available, a transparent screen might be used for augmented reality but is not really useful on a laptop/other screen viewing device as currently used). Which is quite common in some applications (small passive LCDs) but usually not for TFT screens.

A purely reflective screen has no backlight, so it is rendered useless with bad light situations.

So to overcome this, there are transflective displays, which are partially reflective and partially transmissive. These allow a backlight and can use reflection as well, but both to a less extend than their pure counterparts.

There is (or was) a laptop around which had a transflective screen.

Probably the main problem for them not being used commercially are:

  • Costs (adding transflective layers is expensive)
  • appearance when not in sunlight (e.g. in the shops) is worse compared to transmissive displays

This article is old, but I guess the arguments haven't changed much.

\$\endgroup\$
0
\$\begingroup\$

If I'm out in the sun with my laptop running low on battery, wouldn't it make sense to use free ambient backlight instead of wasting battery life on illuminating the display?

OLED displays for example are basically LEDs at each pixel location that display the color commanded, so there is no need for illumunation, see this article

https://en.wikipedia.org/wiki/OLED

Apple current Retina screens seem to be a version of OLED, with higher density, per Wikipedia.

\$\endgroup\$
  • \$\begingroup\$ I'm pretty sure OP is mainly asking about LCD displays and the like \$\endgroup\$ – BeB00 Oct 19 '18 at 13:30

Not the answer you're looking for? Browse other questions tagged or ask your own question.