Odd optical effect with LCD screen?
Discussion
Ok, maybe equally a 'Science' thread but hopefully someone can tell me what's going on from a biological angle...
Changed electricity tariffs recently (bear with me), and the new deal comes bundled with an energy monitor. The gizmo tuned up today, so I duly set it up and turned it on. It has a back-lit LCD screen that is normally mono but goes colour when function buttons are pressed to access particular features.
Now, the odd bit... with the mono display lit, and no room light on (was checking the energy used by the room light like a right saddo), my peripheral vision sees the screen as blocks of red and green light (vertically arranged) - look straight on and I see what is intended, glance away and it flashes red and green just before sight of it is lost; both directions. Actually quite disconcerting because it's quite bright and very pronounced just as the thing comes into/disappears from view...
Like many, I have LCD displays all over the gaffe (and at work etc). I've never seen this happen before. I'm guessing it's something to do with the polarisation of the LCD panel... or is my eyes?
Changed electricity tariffs recently (bear with me), and the new deal comes bundled with an energy monitor. The gizmo tuned up today, so I duly set it up and turned it on. It has a back-lit LCD screen that is normally mono but goes colour when function buttons are pressed to access particular features.
Now, the odd bit... with the mono display lit, and no room light on (was checking the energy used by the room light like a right saddo), my peripheral vision sees the screen as blocks of red and green light (vertically arranged) - look straight on and I see what is intended, glance away and it flashes red and green just before sight of it is lost; both directions. Actually quite disconcerting because it's quite bright and very pronounced just as the thing comes into/disappears from view...
Like many, I have LCD displays all over the gaffe (and at work etc). I've never seen this happen before. I'm guessing it's something to do with the polarisation of the LCD panel... or is my eyes?
Peripheral vision does not 'see' in the same manner as central vision as there are many more rod cells at the edge of the retina than the centre. I wrote an assignment (lab report) last year that compared reaction times between auditory and visual stimuli, distance and loudness of noise, colour of signal etc. Sadly I've forgotten most of the nitty gritty but it was very interesting....Ah, sorry for the Wiki link..
http://en.wikipedia.org/wiki/Flicker_fusion_thresh...
http://en.wikipedia.org/wiki/Flicker_fusion_thresh...
Per that link "Fast-moving flickering objects zooming across view (either by object motion, or by eye motion such as rolling eyes), can cause a dotted or multicolored blur instead of a continuous blur"
It's the same reason that I, when looking at LED car tail lamps, can see a dotted line when flicking my eyes from side to side over the rear of the car. (Because they flash on and off very fast using "pulse width modulation" i.e. varying the on/off time ratio, to vary the intensity for driving lights vs brake/fog lights. The effect when looking directly at them is the intensity reduces when they're flickering, but moving my eye quickly over the car reveals the dotted line resulting from the on/off switching.)
It's the same reason that I, when looking at LED car tail lamps, can see a dotted line when flicking my eyes from side to side over the rear of the car. (Because they flash on and off very fast using "pulse width modulation" i.e. varying the on/off time ratio, to vary the intensity for driving lights vs brake/fog lights. The effect when looking directly at them is the intensity reduces when they're flickering, but moving my eye quickly over the car reveals the dotted line resulting from the on/off switching.)
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