Back To Basics: Screen technology explained

June 26, 2013
Welcome friends, to the “Back to Basics” series where we’ll run a fine toothed comb over each and every aspect of Android so that you can make an educated decision on which Android device is for you.

    Android Authority Back to Basics

    This week’s edition of Back To Basics is going to focus on the part of your device that you’re spending almost all your time looking at. It’s time to talk screen technology.

    No two displays are the same, but there are a few guidelines that can help you choose the right screen for you. From the screen resolution, pixel density, type of display, to even the size, there are a lot of factors that determine whether a display is good or not, but fear not, read on as we explain what to look for in a smartphone or tablet display.

    Screen resolution and pixel density

    The first thing you might hear about your display is the screen resolution and pixel density or PPI (pixels per inch). Due to the vast size and price range of Android devices, there are a wide variety of screen resolutions, so we’ll cover the most popular ones.

    Screen resolutions are commonly written as width x height (e.g: 800 x 480 means that the display is 800 pixels wide, and 480 pixels tall). Here are some of the most popular screen resolutions:

    • 240×320: This screen resolution is most commonly used on really small screens, and/or on budget phones.
    • 320×480: This screen resolution is also used on really small screens (sub 4-inch), and/or on budget phones.
    • 480×800 (WVGA) : A few years ago this was the premier screen resolution and as such was found on many high-end phones like the Samsung Galaxy S2, but now it’s usually reserved for mid-range smartphones with displays that are smaller than 5-inches.
    • 960×540 (qHD): This was also a high-end screen resolution a few years ago, but is now reserved for mid-range smartphones.
    • 1280×720 (HD/720P): To be classified as a high-end smartphone last year you would need a HD display. Some mid-range and high-end smartphones and tablets will be found with this screen resolution.
    • 1920×1080 (Full HD/1080P): Usually reserved for TV’s, Full HD smartphones have come up in a big way this year. A Full HD display is currently exclusively available on high-end smartphones and tablets.
    • 2560×1600 (WQXGA): This is an insanely high resolution which is currently found on the Nexus 10, and is exclusively available on high-end tablets.
    The Nexus 10 comes with an insanely high resolution.

    The Nexus 10 comes with an insanely high resolution.

    When it comes to screen resolution there are a lot of factors. On smaller displays and cheaper smartphones you’ll see lower screen resolutions, and on larger displays or high-end devices you’ll see higher screen resolutions.

    Pixel densities are important when it comes to the overall sharpness or the display, which is important for reading web pages or e-books. Pixel densities vary due to the screen resolution and size. If the display is large, but the resolution is low, the PPI (pixel per inch) count will be lower.

    A pixel density higher than 300 PPI is great, a pixel density lower than 100 PPI is considered poor, and a pixel density between 200 and 300 PPI is considered reasonable.

    It’s a widely held belief that a pixel density above 300 PPI is considered great, and most won’t be able to see any jagged lines, or pixels. A pixel density lower than 200 is considered poor and is usually found on low-end devices, and a pixel density between 300 and 200 is considered reasonable and is usually found on mid-range devices

    What is an LCD display?

    LCD stands for Liquid Crystal Display, and is the most popular display type for mobile devices. This is due to its relatively low power consumption and good image quality.

    TFT Display

    The most popular type of LCD display is the TFT display, which stands for Thin Film Transistor display. This display tends to be the best type of mobile LCD displays.

    TFT displays provide greater contrast and improve response time, however are more expensive, and less power efficient.

    It has a transistor next to every pixel, and therefore allows each individual pixel to be turned on and off. This improves response time and provides greater contrast than other types of LCD displays. However, they also tend to be the most expensive, and less power efficient.

    IPS panels

    Some high-end smartphones and tablets use an IPS (In-plane switching) panel which is a type of TFT panel, but improves upon some of the drawbacks of a regular TFT LCD panel. IPS panels produce consistent and accurate color from all angles. Therefore, they have wider viewing angles than regular TFT displays, which is great for people who watch videos with a group of friends.

    Super LCD

    Manufactured by Samsung, but used mostly by HTC, Super LCD is a display technology which removes the air gap between the outer glass and the display elements. This reduces the glare, and also consumes less power and has better outdoor visibility than regular LCD screens.

    htc one vs sony xperia z both standing aa

    The Super LCD3 display of the HTC One on the left, and the TFT display of the Xperia Z on the right.

    The latest version of Super LCD is Super LCD3 and is said to consume less power than previous versions. It is found on the HTC Butterfly, HTC Droid DNA and HTC One.

    What is an OLED display?

    OLED stands for Organic Light-Emitting Diode, and an OLED display consists of organic polymer which lights up when charged with electricity. It offers many advantages over LCD displays as it is thinner, brighter, more power efficient and provides wider viewing angles. They also provide much better contrast and response times.

    The most popular type of OLED panels on mobile devices is AMOLED technology. AMOLED stands for Active Matrix Organic Light-Emitting Diode and is even more power efficient than standard OLED displays.

    The largest manufacturer of AMOLED displays is Samsung, which markets its displays under the Super AMOLED moniker. Most of Samsung’s high-end and flagship smartphones use Super AMOLED panels, however some use LCD panels.

    samsung_oled_pentile_matrix_comparison

    Comparison of a conventional subpixel structure, and the PenTile Matrix structure.

    Samsung has sometimes used a PenTile matrix on its displays. This uses two subpixels inside every pixel in a RGBG (Red-Green-Blue-Green) structure, instead of the standard RGB (Red-Green-Blue) structure. Some have criticized PenTile displays for overall fuzziness, but most agree that at higher pixel densities the fuzziness is not apparent. The PenTile matrix is used by Samsung for longer life of display, as the blue subpixel degrades faster than the other subpixels in OLED panels.

    AMOLED VS LCD: Which is for you?

    Both display technologies offer advantages and disadvantages. AMOLED screens have higher contrasts and deeper, true blacks, but LCD’s tend to offer more accurate colors. While AMOLED displays are brighter when viewed off-center, LCD panels can be viewed more easily under direct sunlight.

    AMOLED displays tend to be more power efficient overall, however, LCD panels are more power efficient when it comes to displaying web pages. AMOLED screens have better viewing angles, but LCD panels tend to be sharper on lower resolution panels thanks to the use of the RGB structure instead of PenTile RGBG.

    Outdoor shot (daylight); screens on max brightness; screens reflecting sunlight

    The Galaxy S4 (left) uses a Super AMOLED display and the HTC One (right) uses a Super LCD3 display.

    Of course, people looking for a budget smartphone won’t find many devices utilising AMOLED displays (unless they are older Samsung Galaxy S smartphones), so they would be looking at LCD panels. People looking for mid-range devices will face the same situation, however, there are a few devices available using AMOLED displays. In the high-end market for smartphones there is a bigger question on which display technology is best.

    Wrap up

    Overall, it depends on whether you prefer the true blacks and high contrast of AMOLED displays or the accurate colors and direct sunlight performance of an LCD panel. In the tablet market there is no doubt as to which display you should use, since the tablet market almost exclusively uses LCD panels.

    If you’d like a direct comparison between smartphone displays you can check out some of these links:

    We’ll be back next week with another edition of the Back to Basics series, but if you have a question about Android, head over to our AA Q&A page, where our team will answer your questions every Wednesday, or just drop your questions in the comments below and I’ll be happy to respond.

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    Comments

    • MasterMuffin

      I wonder why Samsung isn’t making 1920×1080 AMOLED screens for its tablets, too pricey? Anyways (I think) OLED is the future, it just is so new compared to LCD that it doesn’t beat it yet. In the future there will be no Pentile and color calibration will be done better. And flexible displays can only be oled, right?

      • Adam Koueider

        I think Samsung should first start making regular Full HD displays on their tablets, then we can worry about an AMOLED display. As to the question, not necessarily. Samsung has another technology called Super PLS (Plane to Line switching) which is also capable of being flexible.

        • MasterMuffin

          Yea it’s annoying how they make tablets with displays that have so low PPI. About that Super PLS, I cam’t find any information about it other than some articles from 2010 or 2011 that say its max resolution is 1280×768

          • Adam Koueider

            Well the Galaxy Note 10.1 uses a Super PLS display, but I don’t think Samsung is going to put too much emphasis in it, because its basic use was if Super AMOLED’s couldn’t reach FHD, but since they figured that out, I don’t think they’ll do much with it. They’ve got Super LCD as well if they really need it, but I think Samsung wants its high-end devices all to be using Super AMOLED.

            I think the only reason why the Galaxy S4 Active doesn’t have a Super AMOLED is because Samsung just can’t make enough for the regular S4 and the Active.

            • MasterMuffin

              Okay thanks :)

        • Trent Richards

          It baffles me that the Samsung made Nexus 10 has the highest resolution on the mobile market yet none of the Samsung branded tablets have so much as full HD.

    • mobilemann

      Overall, it depends on whether you prefer the true blacks and high contrast of AMOLED displays or the accurate colors and direct sunlight performance of an LCD panel.

      very good summary. my sgs3 is horrible in direct sunlight, basically unusable.

      • Trent Richards

        I have to crank the brightness to the max on my GS3 when in direct sunlight. At that point the screen is viewable, but falls well behind competing LCD screens.

        • mobilemann

          we agree on something!

          • Trent Richards

            Probably more than one thing.

    • RarestName

      What about DPI?

      • CRiTiCaL_FLuX

        People and companies seem to use the terms PPI (pixels per inch) and DPI (dots per inch) interchangeably now, although I believe they’re technically not the same thing.

      • Trent Richards

        DPI is dots per inch and used to rate the sharpness of printed material.

      • Adam Koueider

        What @trent_richards:disqus says is correct, DPI is more commonly used for printers, while displays use PPI.

    • jamie

      AMOLED is brighter? I thought LCD was brighter?

      • Adam Koueider

        Sorry about that, it should have said “AMOLED displays are brighter when viewed off-center”, Fixed.

    • http://annunakimaster.blogspot.com/ AnnunakiEnvoy

      Dear Author, I would ask you to write something about “pen technology -back to basics”.
      e.g. s-pen, c-pen, handwrite, pencil and metal pen used by sony to write in their latest phablet.

      • Adam Koueider

        Sure thing, I’ll add it to the list. It’s a pretty long list so you might have to wait a while (sorry).

    • Patato Hsieh

      SLCD still manufactured by Samsung? I heard it’s Sharp making the panels(or at least some other manufacturer)? Not 100% sure though.

      • Adam Koueider

        S-LCD used to be owned by both Samsung and Sony (I think that’s the manufacturer you were referring too), but Sony sold all its shares in the company to Samsung to make S-LCD corporation a wholly owned subsidary of Samsung.

        • Patato Hsieh

          I see. Thanks for your reply!

    • Jonyong

      Dear Adam,

      Back to basics I would really love, appreciate and enjoy if you can explain the whole mechanics and relationship in regards to ARM processor. It will be a very good and long article on the same architecture by ARM but different manufacturer employing different design on both processor and GPU. Thanks and Cheers.

      • Adam Koueider

        We’ve got a Back to Basics on processors coming up in a few weeks (possibly next week). Stay tuned.

    • Jason

      AMOLED sucks under sunlight………really suck

    • ahmed

      whos better a screen with 4.3 inch qhd super amoled or a screen with 4.3 1280*720 tft

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