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Science popularization: Is the black border on the phone screen unavoidable?

Discussion in 'General Mobile Discussion' started by htfan, Mar 18, 2016.

  1. Today I going to share some knowledge about the black border on the phone screen.
    Have you noticed that there is a "black border" between the phone screen and the frame?

    In fact, this is not an issue particular to the cell phone. We can see "black borders" on the screens of other common digital products, such as tablets, PC and TV.

    What on earth is the black border? Is it necessary?

    According to Baidu.com, the black border is artificially designed, and its nomenclature is BM area. While being assembled, the screen of each phone has error and can't be absolutely aligned. If the screen frame is aligned with visible edges of BM area, bright borders will appear around the screen. Therefore, the primary function of the BM area is to prevent light leakage. Some phone screens show obvious light leakage due to the issue of screen assemble and the BM area cannot effectively conceal it.

    Can the black border on the phone screen be narrowed?

    The width of the BM area is affected by three factors: The width of the LCD screen frame (a); the gap between the LCD screen and the front cover (b); and width of the dispensed adhesive between the panel and the front cover (c).

    1)First, the width of the LCD screen is determined by the component itself and the choice of the manufacturers. Currently, the width of the LCD screen of the mainstream manufacturers is between 1 and 1.4mm;

    2)The gap between the LCD screen and the front cover is affected by assembly technology. The greater the technology, the closer the gap.

    3)The width of the dispensed adhesive can't be narrowed infinitely. The best technology of the industry can make it as narrow as 0.4 to 0.5mm. Excessive narrowing the width of the dispensed adhesive may affect the reliability of the LCD components, and the adhesive of the lens may break off.

    The black border is widely existing, and the width of the black border is generally above 1.7mm. To narrow or eliminate the black border is depends on the technological breakthroughs in components, assembly and adhesive. Many manufacturers (I will not reveal their names) have managed to narrow the border to the largest extent. This actually harms the interest of the consumers!

    Since the black border can't be narrowed, is there any method to visually conceal the black border?

    The general practice of the industry is to paint the black border in the same color with the glass panel in order to hide the black border. When the screen is lit up, the screen seemingly has no black border. But when the screen is turned off, the physical border of the phone looks wider. Currently, iPhone 6s Plus is using this technology. Meanwhile, we have noticed that some manufacturers have adopted a different method--using curved glass to weaken the black border.

    Let’s use Huawei Mate 8 as an example, the actual width of its black border is 1.7mm, representing an advanced level in the industry. At the same time, it has adopted 2.5D drilled and cut float glass, which effectively narrows the width of the black border visually but will not affect the visual effect of the physical frame of the phone.

    Huawei is killing two birds with one stone!
    HauntedHearts likes this.
  2. good read. Thank you :droid:
    htfan likes this.
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