Quetelet rings on LCD displays?

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In summary: I saw the same interference pattern on two laptops, Asus Vivobook Flip 14 and Lenovo Chromebook Ideapad Flex 5. Here too, any dust had been wiped off the screen, so that Quetelet rings were not to be expected.
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Orthoceras
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When shining a flashlight at particular LCD displays, an interesting interference pattern appears, consisting of parallel or concentric lines. It closely resembles Quetelet rings seen on dusty mirrors and glass panes. Quetelet rings are formed when light from a dust particle interferes with the light from its mirror image.

For example, when shining a flashlight at a digital whiteboard (brand Prowise), such a pattern appears. When moving the flashlight in circles around your eye or the camera lens, the pattern will rotate, without any preferred direction. If you move the flashlight laterally towards your eye or the camera lens, the distance between the interference maxima increases, as illustrated in this video (link). The digital whiteboard was clean, no dust on the glass, so the necessary condition for Quetelet rings seems to be missing.
Quetelet combi.png

C is the position of the mirror image of the camera lens, Ln is the position of the mirror image of the flashlight. Top - camera and lamp equally remote from the screen: interference pattern consists of straight lines. Bottom - camera closer to monitor than lamp: interference pattern consists of concentric circles.I saw the same interference pattern on two laptops, Asus Vivobook Flip 14 and Lenovo Chromebook Ideapad Flex 5. Here too, any dust had been wiped off the screen, so that Quetelet rings were not to be expected.

In summary, two questions are:
1) is it right to call the interference pattern that appears on these LCD displays Quetelet rings?
2) how does this pattern arise at these screens? Which 'particles' have replaced the conventional dust particles? Google wasn't very helpful.
 
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Science news on Phys.org
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Orthoceras said:
Which 'particles' have replaced the conventional dust particles?
You may be seeing the random dust effect from a transflector, used in low-power all-light-readable displays.

The transflector is a part-silvered scatterer, formed by random deposition on a layer of polymer. It is placed in front of the backlighting, at the back of the LCD sandwich.
https://en.wikipedia.org/wiki/Transflective_liquid-crystal_display
 
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You may be right, but I am not sure what the equivalent particles are, and how they could be photographed. For the time being I prefer thinking the equivalent particles are actually etched micro pits into the smooth glass surface, created for a matte appearance. I took the picture below with my smartphone and a tiny macro lens, accidentally at the right focal distance. Recording it was difficult because my smartphone has an autofocus that seems to avoid focussing at this very narrow surface layer depth.

Prowise2.jpg
 
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FAQ: Quetelet rings on LCD displays?

What are Quetelet rings on LCD displays?

Quetelet rings, also known as Newton's rings, are a series of concentric circles that appear on LCD displays when pressure is applied to the screen. They are named after the Belgian mathematician Adolphe Quetelet, who first described them in the 19th century.

What causes Quetelet rings to appear on LCD displays?

Quetelet rings are caused by the interference of light between the glass surface of the LCD display and the air gap created by pressure. This interference creates a pattern of concentric circles that can be seen when the display is viewed at an angle.

Are Quetelet rings a sign of a faulty LCD display?

No, Quetelet rings are a natural occurrence on LCD displays and are not a sign of a faulty display. They are a result of the manufacturing process and do not affect the functionality or quality of the display.

Can Quetelet rings be removed from an LCD display?

Quetelet rings cannot be removed from an LCD display as they are a result of the display's construction. However, they are only visible when the display is viewed at an angle and should not affect normal use of the display.

Are Quetelet rings common on all LCD displays?

Quetelet rings are common on most LCD displays, but their visibility can vary depending on the quality and construction of the display. Some displays may have more pronounced rings, while others may have none at all.

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