Comparative study of device screens

This is an analysis of a phone screen, a laptop screen, and a TV screen.

Pixels are visible in three colours – red, blue and green – in all the screens, but the pixels of each screen differ in shape and size. There are variations in the pixel densities. Based on the pixel density, the approximate size of one pixel can be calculated.

Smartphone Touchscreen

Pixel density: 326 ppi

Pixel size: 78 μm

The individual pixels are not clear, but are seen as continuous bands of colour. The space between them is white.

Laptop Screen

Pixel density: 112 ppi

Pixel size: 227 μm

Pixels are much larger than those of a phone screen. They are distinct, and the space between them is black.

Bright blue screen

Yellow screen

Red screen (PowerPoint theme colour)

Dark green screen (Excel theme colour)

Blinking cursor on white screen
A cursor is six pixels wide!

TV Screen

Pixel density: 53 ppi

Pixel size: 479 μm

These pixels are the largest of all. They also have an arrowhead-like shape, compared to the rectangular pixels of the laptop and phone screens. They are spaced close together, in continuous bands.

Pixels shown along with the colours they are displaying

CookerBird

3 Comments Add yours

  1. Manu Prakash says:

    Just such a delightful post! So puzzling to see why TV screens have tilted pixels. I can see why pixel sizes are different – but the tilt is hard to explain.

    Only reason I could come up with is if it helps in manufacturing. Amazing observation!

    cheers
    manu

    1. CookerBird says:

      Thank you @Manu Prakash!

      The TV pixels are quite strange indeed. In fact, the arrowhead shape seems to contradict manufacturing ease and better display (https://superuser.com/questions/1019825/why-are-pixels-square#:~:text=Two%20reasons%3A,pixel%20contributes%20to%20the%20image).

      Another contradiction is that pixels are generally described as being square (though I have never encountered a screen with square pixels), and hence the pixel density remains the same irrespective of whether it is measured lengthwise or widthwise. In the case of rectangular pixels (like those in a laptop or a phone), it isn’t clear whether the pixels per inch are along the length of the pixels or their width. So, the exact “size” of the pixel cannot be determined. The values that I have calculated could be either the length or the width of the pixel, depending on how the pixel density has been measured.

      I also wonder why some screens have black spaces between the pixels while others have white spaces. One of the laptop screens I observed had white spaces, and the pixels weren’t too clear under the Foldscope. Is it possible that the colour between the pixels influences the display in any way?

      CookerBird

  2. Prithvi says:

    When I tried from my foldscope I can’t see anything 🙁

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