Develop Bugs

Amoled black isn't as black as we thought?

I've found out, that the Amoled can't display perfect black. I tried the desktop clock thing, the blackle Google page (scrolled to black only area), and I made a photo in PhotoShop completely black and open it up in gallery.
What I noticed is, that the screen still is displaying something when it should be black. This is very easy to see if you put the phone to sleep when displaying such black.
What am I missing? Doesn't the Amoled completely turn of a pixel that is black? Can someone try to replicate this?
Do you think it's possible that I have an lcd desire and just don't know it?
Sent from my HTC Desire

I have also a Hero (with lcd display) and black on my Desire is "more black" than Hero's
For me it's ok

If you look at LCD screens through a circular polarisation filter you'll sometimes see coloured patterns on it, or it will get completely filtered out at a certain angle. To the best of my knowledge, OLEDs don't emit polarised light, so if you've been to see Avatar or another movie in Real3D and walked away with the glasses then you can use them as an LCD detector...
(The blacking out effect works as a cool CSI-esque monitor dust detector)

No disrespect, but... who cares???
So the blacks are not as deep as say, a Kuro plasma. This is a smartphone, not a home theater tv.

Jaa-Yoo said:
No disrespect, but... who cares???
So the blacks are not as deep as say, a Kuro plasma. This is a smartphone, not a home theater tv.
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Click to collapse
no disrespect but,...
well real black "off pixel" don't use power so all the people who care about batterylife might care...
s.

I don't think they do emit light on blacks. I have noticed that in a completely dark room I can't see blacks on my Desire at all, it emits no visual light. Maybe the black you were testing isn't pure black.
Sent from my HTC Desire

"It's like, how much more black could this be? And the answer is none. None more black."
Couldn't help myself
Sent from my HTC Desire using XDA App

I do agree that it is much better than any lcd. BUT black should be no light at all. When you turn off the screen when all the pixels are supposed to be off, you see a change. You can also see the outline of the screen when it is in any of the previously mentioned methods of darkness.
Sent from my HTC Desire

I did the following test :
- found a room where I could be in complete darkness
- used the following enclosed file (a pure RGB=(0,0,0) 800x480 png file) and displayed it fullscreen on my phone.
- use the palm of a hand to cover the 4 lit buttons
- the screen is pretty damn BLACK ! (an LCD screen, next to it, also displaying black pixels, would look like a torchlight)
- After a minute or so, the eyes getting used to the darkness, I could very slightly see the screen. I don't know how the phone is built, but I'm guessing it's a light "leak" coming from the LED(s) of the 4 buttons.
I tried this procedure at various brightness settings (from min to max) : the remaining light coming from the screen did not change.
Is there a mod to kill the buttons backlight ?

It is possible to kill the backlights, but have not tried it myself.
http://forum.xda-developers.com/showthread.php?t=704977&highlight=buttons+backlight

Ok, switched off the buttons backlight thx to Flaggie. The screen indeed still emits some light when displaying a full screen black picture. Strange.
It would be interesting to get an explanation from HTC about this, but i'm pretty sure it pointless hoping they would reply to such a question. I'll give it a try...

Perhaps you hae one of those new Desire models with a LCD screen?

No, I bought it the day it came out. Try out on your own. The test I detailed is pretty straight forward...

kekkle said:
Perhaps you hae one of those new Desire models with a LCD screen?
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That is what I thought at first, but than the amount of light on dark would change when you change the brightness.
I want to know what HTC has to say about this.
PS: I bought my phone in June.
Sent from my HTC Desire

OMG does any of you know how a led screen works? lol Active Matrix Organic Light Emitting Diode its name clearly states that the pixels are self-illuminating so clearly unless the screen is of the display is always going to give some light off

It is actually the other way around. They are self emitting, they can turn off. LCDs, however have a backlight, which doesn't turn off, so some light still passes through.
Sent from my HTC Desire

OLED can havae infinate contrast ratios. I have a cowon s9, it has an OLED screen and in a pitch black room you cannot tell it's on. The desire does emit some light even on true black :-/

AndroHero said:
OMG does any of you know how a led screen works? lol Active Matrix Organic Light Emitting Diode its name clearly states that the pixels are self-illuminating so clearly unless the screen is of the display is always going to give some light off
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OMG please read the Wikipedia article...

Unlike over saturated colors and Pentile jagginess which are clearly visible and to some point distracting (at least to me) this seem like pure academic issue, since it can be visible only in total darkness and even then it is not visible unless screen is completely black.
What would be practical purpose in looking at black screen in darkness?

vlasac said:
Unlike over saturated colors and Pentile jagginess which are clearly visible and to some point distracting (at least to me) this seem like pure academic issue, since it can be visible only in total darkness and even then it is not visible unless screen is completely black.
What would be practical purpose in looking at black screen in darkness?
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I agree. This is an academic issue, but aren't you a bit disturbed by the fact that there has been soo much talk about this oled screen and its pure black, and it was all a lie?
I think the problem might be in the image to screen processing where it gets converted to the pentile matrix(and over saturated).
Sent from my HTC Desire

Replacement HTC Desire has a washed out screen :(

The phone also feels tangibly heavier.
Think it may be a Super LCD screen rather than AMOLED (how can I check?). Overall, the screen just looks grey. I want my old AMOLED one back?!

Some things to try:
- look at the screen through a circular polarisation filter, eg. RealD glasses (no idea if this works with SLCD...)
- set brightness to maximum and display a black image in a dark room
- look really closely at the screen with a magnifier (or someone with good eyesight) to see if it's Pentile (I guess an LCD screen could be Pentile too...)
- weigh the phone on some good scales to see if it really is any heavier

I've weighed it - and it's just a bit higher than 135 grams. Even though it matches the spec listed on HTC's website, I still think my previous phone was lighter. Now to test the AMOLED screen. Hmm..

Schmeggma said:
Some things to try:
- set brightness to maximum and display a black image in a dark room
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Click to collapse
the backlight is apparent then. when i switch the phone off, it goes completely black, otherwise it's a grey colour. does that mean it is not AMOLED?

It certainly sounds like that may be the case
Would you be able to post pictures? This is bad news for anyone wanting a replacement. AMOLED was a big selling point for me.

However,
Can you read it in daylight outdoors?

stats101 said:
the backlight is apparent then. when i switch the phone off, it goes completely black, otherwise it's a grey colour. does that mean it is not AMOLED?
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Click to collapse
If it's LCD, can I have your Desire then? I hate the Pen-Tile pixel layout...

Seems the black wallpaper in the dark test isn't a valid avenue to test if it's AMOLED (see: http://forum.xda-developers.com/showthread.php?t=725656).
Think it may be either me just imagining things - or a defective AMOLED screen.

I'm sending my Desire for repair as I have dust under my screen, I contacted HTC support worried if I may get an LCD screen and they asured me they are currently still using AMOLED displays only

tell me if my screen looks washed out to you. I'm sure my last desire, the colours were a lot more vivid.

Can't really tell if it looks washed out in a photo with nothing to compare it to, but it's definitely a Pentile matrix...

Yes, definitely Pentile. Damn.

Well to me it looks ok and very much the same as mine. I have never returned my Desire to be fixed.
My colors are very vibrant and i can see the screen on daylight (using auto-brightness).
I have noticed one thing on your photos though: your Internet icon is different from mine. Yours seems an older icon, really washed out, being gray and having the home icon. Mine looks more recent, it's a earth icon in blue (same blue as the mail or message icons) with some orbits rotating around the world...
Could this be it?

Necroman_AI said:
Well to me it looks ok and very much the same as mine. I have never returned my Desire to be fixed.
My colors are very vibrant and i can see the screen on daylight (using auto-brightness).
I have noticed one thing on your photos though: your Internet icon is different from mine. Yours seems an older icon, really washed out, being gray and having the home icon. Mine looks more recent, it's a earth icon in blue (same blue as the mail or message icons) with some orbits rotating around the world...
Could this be it?
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Click to collapse
The internet icon i think is Orange's reworking (notice the orange door to the house).

I just wanted to mention, I 've had 5x different Desires and some have had a more vibrant screen to others.
Through the range of brightness from minimal to maximum I've definitely been able to see that some of the handsets are bright but seem to have very slightly less clarity, whilst others have a sharper image but loose some vividness.
I prefer the brighter / more colourful one I have now.

teffers said:
I just wanted to mention, I 've had 5x different Desires and some have had a more vibrant screen to others.
Through the range of brightness from minimal to maximum I've definitely been able to see that some of the handsets are bright but seem to have very slightly less clarity, whilst others have a sharper image but loose some vividness.
I prefer the brighter / more colourful one I have now.
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Click to collapse
5 Desires. I've been through 3 so far. The first two were very similar (although the second one for some reason just felt so much lighter). This one is washed out. Going to try and phone Orange and try and see if I can have another one sent. :/

[Q]Black pixels still on when black?

So i was watching a youtube video this morning comparing the evo and the epic.
The gentleman said that with the Epic when there are black pixels, they are actually off. With the EVO the pixels are on but displaying a black color.
Ii always thought they were off regardless but it was interesting to hear.
Here is the video for your viewing pleasure also
http://www.youtube.com/watch?v=8dkbbwzeb-w

LCD has a backlight. To keep the backlight from shining through, you need to turn your pixels on and hence you get black. Thats why the most power friendly color is white on an LCD. For OLED, since they don't have a backlight, black is actually when they turn the pixel off. So the most power friendly color for that technology is black. The same applies to CRT except that pixels are activated with an electron gun.

Minjin said:
LCD has a backlight. To keep the backlight from shining through, you need to turn your pixels on and hence you get black. Thats why the most power friendly color is white on an LCD. For OLED, since they don't have a backlight, black is actually when they turn the pixel off. So the most power friendly color for that technology is black. The same applies to CRT except that pixels are activated with an electron gun.
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Makes one hundred percent sense. Hats off to you good sir.

[FYI] AMOLED or SLCD - HTC response

FYI - Can HTC tell whether your phone has an AMOLED or SLCD screen?
Short answer:
No.
Longer answer:
I bought my phone from Orange and thus the box comes Orange branded. Therefore, it doesn't say on the box whether than phone is AMOLED or SLCD (referred to as multitouch or something like that). I contacted Orange who haven't got a clue and just told me is AMOLED by reading their stock description. I contacted HTC UK and gave them the serial number of the phone. They said that at this present time there was no way for them to decipher whether I had an AMOLED or SLCD screen. There may be in the future but at the moment there is not.
The one bit of interesting information HTC could provide is that 90% of their stock is AMOLED and 10% is SLCD.
The reason I looked into this is because I can't really tell from the videos online what screen I have. There are some murmurings that all SLCD phones are bootloader 0.83 (what I have) but unfortunately not all 0.83 phones are SLCD.

http://pocketnow.com/android/how-to-tell-if-your-htc-desire-has-slcd-or-amoled-screen

Already read that. And I'd say it's actually pretty difficult to tell unless you have their exact screenshots.
And a magnifying glass!

The box for mine said "3.7-inch touch-sensitive screen", but it has the 0.75 HBOOT, so I really need to find a magnifying glass to check it.

tinytjf said:
Already read that. And I'd say it's actually pretty difficult to tell unless you have their exact screenshots.
And a magnifying glass!
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If it's so hard to tell why bother?

It really is easy to tell
Go into a dark room and go into the settings menu (which has a black background colour). If the black is lit at all or slightly grey, you have SLCD. If it is totally black (and I really mean no light at all) you have AMOLED. I have both and it really is easy to tell them apart in by the contrast of the settings menus, not so easy otherwise.

familyhousing said:
Go into a dark room and go into the settings menu (which has a black background colour). If the black is lit at all or slightly grey, you have SLCD. If it is totally black (and I really mean no light at all) you have AMOLED. I have both and it really is easy to tell them apart in by the contrast of the settings menus, not so easy otherwise.
Click to expand...
Click to collapse
that's not entirley correct. I have Amoled, and even in a dark room, it's not 'totally' black.

BarnOwl said:
If it's so hard to tell why bother?
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Click to collapse
Because there are some rooting methods that require you to know whether you're on SLCD or AMOLED... Having said that there are workarounds but it would be nice to know which method before I start.
As for the dark room idea, I'll try it. Thanks.

I'm 99% sure mine has an AMOLED screen because the bootloader was 0.80 (before the 2.2 upgrade)
My box didn't mention AMOLED on the box (so it could have been either)
One thing I have noticed is that a block of white against a darker background appear to have a slight pinkish toothcomb on the left edge of the white block (eg the HTC clock widget that's usually on the main home screen.
I believe this is a sign of the pentile arrangement of pixels that you get in the Desire's AMOLED screen.
ie:
****
****
Without a magnifying glass though its difficult to be certain.

Do what I did:
http://forum.xda-developers.com/showpost.php?p=7257878&postcount=10
Take a picture of the phone with a macro zoom camera. The pentiles become easily distinguishable.

i had both amoled and slcd side by side and all i can say is that the difference is huge...
if open your browser and set text size to large and than browse to xda forums... with amoled you won't be able to read clearly without zooming in, but on slcd you will be able to read and see everything clearly..
other than that amoled is brighter and has more contrast but slcd has a lot more clearer picture, that is easily visible when you put two phones side by side
for me slcd is a lot better.

mr.vandalay said:
i had both amoled and slcd side by side and all i can say is that the difference is huge...
if open your browser and set text size to large and than browse to xda forums... with amoled you won't be able to read clearly without zooming in, but on slcd you will be able to read and see everything clearly..
other than that amoled is brighter and has more contrast but slcd has a lot more clearer picture, that is easily visible when you put two phones side by side
for me slcd is a lot better.
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A work colleague has just received his Desire and one of the first things he did was compare it to mine. He has an SLCD screen and I have AMOLED. When placed side by side the difference is gobsmackingly obvious. On the SLCD text appears far smoother, although the colours do appear to be washed out.
I agree that the SLCD is better, but I will say that I am more than happy with my AMOLED screen.

stats101 said:
that's not entirley correct. I have Amoled, and even in a dark room, it's not 'totally' black.
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Ok, I exaggerated a little. I actually have an AMOLED Legend and an SLCD Desire. Just for my own sanity I checked again and the Legend AMOLED screen does have totally 100% blacks, even in a completely dark environment. I assume an AMOLED Desire would be the same and hence as easily identifiable.
If you think about it, AMOLED will always produce complete blacks as each pixel is not even powered for black output. The light you report to see on an AMOLED screen can only be explained by reflection. If your screen emits light from 100% black areas then you have SLCD.
Sent from my HTC Legend using XDA App

Well,one easy way is to put it next to your computers monitor while it shows a black image.The phone should be in the settings menu.If both seem about the same colour,you have an SLCD.If the monitor's picture seems grey while the phone's is pitch black,it's AMOLED.
I hope it helps those who don't have two devices to compare.

I have both the AMOLED and SLCD Desire. It's a clear difference. Mine has no bleeding around the edges. But It's clear to see the SLCD when the Call screen is on. The AMOLED is a lot blacker where as the SLCD is more gray than black.
The colours are also a lot more vibrant and alive on AMOLED, the SLCD looks washed out. The brightness is also higher on AMOLED.

You dont need magnifying glass. Droplet of water on screen will do.

I will be getting a Desire tomorrow or the next day and I don't know whether I'll get AMOLED or SLCD, so I want to know, are their quality worlds apart? Would it really make a difference to have either one of those? Is one better? How does both of them compare to iPhone 3GS's screen?

To the average person both are very very similar and you would not notice a difference without knowing there was two sorts of screens.
Chances are you won't get a choice of which to get, it just depends what is in stock.
Stat wise SLCD takes it on paper as being the best, but only marginally.
Honestly it really doesn't matter which you get, unless you compare two devices side by side you won't even know.

Because of the pentile matrix on the AMOLED, I would go with the S-LCD. The AMOLED is said to be over saturated in dark environments, and unable to read in the sun. I'd rather have balanced colors inside and readable screen outdoors. Also, the S-LCD have a real 800x480 resolution

Had both side by side for a while.
They are absolutely equal in bright sunlight. That said, people suspect that some amoled screens come out of the factory better than others.
Blacks, contrast and bright colours are absolutely better on the amoled
Bright whites and overall colour balance is probably a bit better on S-LCD
Pixel smoothness and small text readability is a bit better on S-LCD. That said, after you have amoled for a while you will realize that unless you keep your nose touching the screen, your vision will process the amoled screen the same way as the S-LCD. Takes some time though.
Battery usage: we made -accurate- -measured- tests, of the battery drain in milliamperes/milliwatts. They came out very close, the main difference is obviously that amoled display is optimized for displaying dark stuff. Overall I think you save a bit of battery with amoled, but anyway the results were that:
- on low-medium brightness (inside) amoled is almost always better. If you are displaying all white screen, they are closer
- on medium brightness it depends on what you are displaying (light vs dark) but there is not a lot of difference, although amoled tends to save a bit more
- on high brightness (outside) amoled almost invariably drains more than S-LCD, except when the screen is very dark. When displaying almost completely white screens at max brightness, amoled loses big time compared to S-LCD, but that is the only situation where this big difference happens.
One last noticeable difference is colour temperature, but that also varies from handset to handset. Amoled tends to be a bit on the warm side (at least on mine) and S-LCD on cool. The old 'problem' of the pinkish tint is gone with the froyo update, those few displays still affected by it could be counted as defective.
Oh and by the way, here almost invariably if the box doesn't say 'amoled' you are getting a S-LCD screen. I have to admit I was very surprised at first by the quality of S-LCD and mistaken it for a differently calibrated amoled for some minutes. Blacks are good, but not close to amoled, if you go into a dark room you should notice

This phone doesn't need inverted / black ?

Having used so many Samsung phones with AMOLED screens, it was always recommended to use black apps, and dark wallpapers to save battery life, that white is a big battery drain on AMOLED.
Now with the One X being S-LCD2, I thought we don't need to use black as much ? Is white apps, and lighter wallpapers OK on this phone ? White is not a battery drain on the One X ?
Sent from my HTC One X using xda premium

No, it's backlit, which is why it's brighter.

AMOLED can turn off the pixels that need to be black, saving power. LCD, on the other hand, can not.
The One X has an LCD screen, so there's no advantage of more black. Exactly the same amount of power being used, regardless of the colour shown.

peedub said:
AMOLED can turn off the pixels that need to be black, saving power. LCD, on the other hand, can not.
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That's not a clear description.
With OLED, the pixels emit light, on black, they emit no light and require no power.
With LCD, the pixels block light (either reflected or backlit), the backlight is always on, always requiring power.
There are many other aspects, such as contrast, brightness, colour gamut, aging effects etc.