Is it possible for screen door effect to get worse?

[jad]

Hi all,

I currently own a 50 inch Sony 3LCD. It's always had a little bit of screen door effect, but definitely not terrible. However, the other day I just seemed to notice it a little more for whatever reason. It's noticeable (if you're looking for it) mostly on scenes where a blue sky might be visible, and the shot is panning. I was just wondering if it's possible for screen door effect to actually get worse on an LCD tv? I have a tendancy to be really anal about little things when I'm noticing them. So it's very possible that I'm just looking for it more now that I've noticed it.

It's always been my understanding that the screen door effect is caused by the LCD technology displaying the pixels so large and close together. So, I would assume it's not really something that could change or get worse. Just thought I'd post my question to see if I could get some clarification. Thanks for any comments ^_^

 

[MDS]

The screen door effect is caused by the gaps between the pixels. There is always some small leakage of light through those gaps and that is why LCDs don't do black as black as say a CRT.

I don't think it can get worse over time because the pixels are fixed and don't move. More likely it's just that you notice it more now that you are aware of it and consciously look for it or the SD signal you are viewing is poor and makes the effect more pronounced.

 

[jad]

Thanks for your post! I figured as much. Like I said, I tend to be nit picky over such things.

 

[mtrycrafts]

Thanks for your post! I figured as much. Like I said, I tend to be nit picky over such things.

Have a read:
http://en.wikipedia.org/wiki/Screen_door_effect

It doesn't say light leakage or it would be white, but the physical spaces between pixels. So, it should be a fixed effect, if this is what you are seeing.
Does it diminish with viewing distance from the screen? That might solve it.

 

[jonnythan]

I could see that a dimming backlight would enhance SDE because the pixels don't shine as brightly and bleed into each other as much. Just an idea.

 

[MDS]

So Mtry you take Wikipedia as always 100% accurate? If so go look up the definition of 'pink noise' and see how wrong it can be at times. [unless it has been fixed recently]

Light leakage is the primary problem to be overcome with LCD. Yes, the light is white and that is why black often isn't so black. The small amounts of light escaping between the pixels causes black to appear dark gray. Whether it is actually the lines of the grid being seen or not I don't know for sure but either way it is the light leakage that is the source of the problem.

I don't notice it unless I am way too close to the screen.

 

[mtrycrafts]

So Mtry you take Wikipedia as always 100% accurate? If so go look up the definition of 'pink noise' and see how wrong it can be at times. [unless it has been fixed recently]

Light leakage is the primary problem to be overcome with LCD. Yes, the light is white and that is why black often isn't so black. The small amounts of light escaping between the pixels causes black to appear dark gray. Whether it is actually the lines of the grid being seen or not I don't know for sure but either way it is the light leakage that is the source of the problem.

I don't notice it unless I am way too close to the screen.

That is one of a number of links with the same info on it. That had a better picture compared to the number of other websites with the same info.
Do you have a link to a credible source?

If the white light is leaking, then you would see a faint white screen pattern, no? and, you would not see those black screen patterns even with white picture shown int eh link, no? Why is that black?

 

[MDS]

If the white light is leaking, then you would see a faint white screen pattern, no? and, you would not see those black screen patterns even with white picture shown int eh link, no? Why is that black?

Are you saying you couldn't see black text on a white background because white light is leaking? It's not like you have Gandalf the White Wizard illuminating things so brightly that everything is obscured but the white light.

The light source for all of these TVs whether LCD flat panel or rear projection is white light. The light is split with a prism and each pixel is actually a triad of red/gree/blue. The electronics control the timing of where the light falls on the triad to obtain color but the pixels can only be made so small and only spaced so closely together. Small amounts of light leak through the gaps between pixels.

I'm not doubting that the effect is due to seeing the structure that holds the liquid crystals together in a grid. All I'm saying is that it is the small amount of light leakage that leads to the effect. It's definitely getting better though. I am now leaning towards the 52" Sharp Aquos and I couldn't detect any SDE even with my face right up against the glass.