LCD flickering on dithered patterns

T4x series specific matters only
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geobel
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LCD flickering on dithered patterns

#1 Post by geobel » Fri Sep 03, 2004 5:54 pm

I have noticed that my T40 LCD (11P8356 0000000 unknown manufacturer) gives some flickering on dithered patterns (for example the one in display mate test). When I display same images on T42 (Samsung panel) or external monitor (Samsung 173P via DVI) no flickering is present. Can anybody else see background flickering on this page:

http://bioweb.uwlax.edu/GenWeb/Evol_Pop ... v_paup.htm

Flickering is most noticeable if one looks from downside of LCD
Any ideas how to fix it?

Gosha
Thinkpad X61t (7762 CTO) 1.6 GHz 2GB RAM Vista Ultimate SP1
Thinkpad T40 (2373-19U) 1GB RAM; T41p fan; Win XP Pro SP3

Flightvector
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#2 Post by Flightvector » Sat Sep 04, 2004 2:15 am

The LCDs I have only do this when scrolling, and also on textures with alternating lines of pixels or differing color. Scrolling asks the pixels to do to much in a little time and results in a large cycling of either color. But I am not very sure about your flicker. Are you running at native resolution? Flicker should not happen otherwise since LCDs do not refresh when the image is constant. A voltage issue could be possible where the pixels are not liking such differences so nearby, or the video card may be having issues. Also, has it always done this before?
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geobel
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Location: USA, ohio
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#3 Post by geobel » Sat Sep 04, 2004 5:40 am

I run my XGA display at native 1024 x 768. I have noticed this flicker effect long time ago in displaymate (free demo version) tests. There is very nice dithered pattern that I always use to adjust phase of analog projectors and LCDs. Surprisingly I found that my T40 LCD does some flicker on this pattern. T40 flicker is however different from analog LCD noise. It looks very much like if I were running CRT at 60 Hz. However I never noticed flicker in any real objects for a year. The link in my above post is the first page were I can see flicker.

Gosha
Thinkpad X61t (7762 CTO) 1.6 GHz 2GB RAM Vista Ultimate SP1
Thinkpad T40 (2373-19U) 1GB RAM; T41p fan; Win XP Pro SP3

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