How to Evaluate Mobile Displays

Since this article was first written, an updated version has been posted here. Check it out. A lot has changed.

In my last blog post I talked about the best mobile devices on the market today. This will be the first in a new series of posts that will help you evaluate each part of a smartphone or tablet. Since the display is the main interface to your mobile device, let’s start with it.

Bigger is Better

Three main parameters are used to specify the size and quality of a mobile display:

  1. Screen size measured diagonally in inches
  2. Screen width and height in pixels
  3. Screen density measured in pixels per inch (PPI)

The Samsung Galaxy Note has a much larger screen than the iPhone 4S

Today’s best smartphones have displays which are 4.3″ or larger. The largest screen available on a smartphone in the U.S. today is 4.7″ and can be found on the HTC Titan. Think that’s big? It is, but mobile displays are going to continue to get larger. The Samsung Galaxy Note, which was recently released in Europe, has a 5.3″ screen.  As screens get 6″ or larger, the line between smartphones and tablets will begin to blur and these devices may no longer fit into your pocket. Is it worth it? If you spent lots of time browsing the Web, playing games or working with business documents the answer could be yes.

Screen Size

Pixels (H x W)

Screen Density

Apple iPhone 4S



326 PPI




256 PPI

HTC Rezound



342 PPI

HTC Titan



199 PPI

Motorola Atrix



275 PPI

Motorola Droid 2



264 PPI

Motorola Razr



256 PPI

Samsung Galaxy S II

4.3” or 4.52”


217 PPI

Samsung Galaxy Nexus



316 PPI

Samsung Galaxy Note



285 PPI

Chart 1: A comparison of popular smartphone displays

Quality Matters Too!

The HTC Rezound has the highest resolution display available today.

Screen width and height is another popular measurement. Today the best smartphones have 1280×720 pixel displays. The Samsung Galaxy Note has an even larger 1280×800 display. Although the total number of pixels is important, it’s not the best indicator of screen quality. The density of pixels is what really matters.  The higher the pixel density, the more detail a screen can display. Although most people think the iPhone 4S has the highest pixel density, they are wrong. The HTC Rezound has a display with a higher pixel density than the iPhone 4S (342 vs. 326 ppi). Even better screens are on the way. Earlier in the year, Toshiba announced a 4-inch screen with a 367 PPI resolution. Pixel densities are likely to hit at least 386 in 2012.

It’s worth mentioning there is some debate over the ideal pixel density. Steve Jobs once said a device with a pixel density of 300 exceeds the limits of the human retina. However, some photographic experts say that number is too low. They believe the ultimate pixel density is 477 PPI. At that point, it’s said the pixels become invisible to an unaided human eye.

What About Tablets?

Screen resolution is one area where tablets can improve. The best tablets have screen densities below 200 while some smartphones have pixel densities higher than 300. Apple is known for their great displays. How does the iPad 2 compare to Android tablets? Let’s see: The iPad 2 has a 9.7″ screen with 1024×768 pixels. The Motorola Xoom has a 10.1″ screen with 1280×800 pixels. Which is better? The Motorola wins on all three categories: screen size, total number of pixels and screen density (with a pixel density of 160 PPI vs. 132 PPI). If you refer to the chart below, you’ll see there are five other Android tablets with even higher screen densities than the Motorola Xoom. Will we see higher resolution tablet screens next year? Definitely! The Lenovo LePad S2007 will have a 216 PPI display and tablets with 2560×1600 screens will be available some time in 2012. These tablets will have a screen density of at least 300 dpi.

Screen Size

Pixels (W x H)

Screen Density

Amazon Kindle Fire



169 PPI

Apple iPad 2



132 PPI

Asus Transformer



160 PPI

Asus Transformer Prime



149 PPI

B&N Nook Tablet



169 PPI

Motorola Droid XYBOARD 8.2



184 PPI

Motorola Xoom



160 PPI

OGT Eros Tablet



188 PPI

Samsung Galaxy Tab 7.0



171 PPI

Samsung Galaxy Tab 10.1



149 PPI

Chart 2: A comparison of popular tablet displays

That’s Not All

Of course pixel density isn’t the only thing that matters when it comes to screen quality. The color accuracy, color vibrancy, brightness, contrast ratio, black level and viewing angle are important as well. The durability also matters. Gorilla Glass screens are more damage resistant than regular displays. Gorilla Glass 2 screens are on the way, so watch for those.

Well, that wraps up my review of mobile screen technology. In my next post, I’ll write about the heart of every mobile device: Its processor.

Thanks for stopping by.

– Rick

Copyright 2011 Rick Schwartz. All rights reserved. Linking to this article is encouraged.

The Ultimate Mobile Device (Updated Feb.)

Since this article was first written, an updated version has been posted here. Check it out. A lot has changed.

Although there are lots of great mobile devices available today, there is no one single device that is best at everything. It is possible to say which phone (or tablet) has the best display, processor and so on. After reading this article, you should be better prepared to purchase the ultimate mobile device based on your needs.

Best Mobile Display

Since the screen is the main interface to your mobile device, it’s very important. Although the size and total number of pixels matters, it’s the pixel density which determines the amount of detail you’ll see. More info.

The Galaxy Note is the the only smartphone with a 5.3" display

  • First place: The HTC Rezound has a 4.3” screen with 1280×720 pixels and a higher pixel density than the iPhone 4S (342 ppi vs. 326 ppi). The Windows Phone Lumia 900 is the most readable under bright light. More info.
  • Runner-up: The Samsung Galaxy Note has the largest screen you’ll find on a smartphone today. It’s an amazing 5.3” and has a record setting 1280×800 pixels. The reason it doesn’t come in first is because its pixel density is lower than the HTC Rezound. When it comes to tablets, the Samsung Galaxy series have some of the best displays available today, and pixel densities which are almost 30% higher than the iPad 2.
  • What to look for: A tablet with a 2560×1600 pixel screen will be available in 2012. Smartphones will get screens with pixel densities near 400 ppi as well. Also expect to see displays with polarized filters, that make screens more visible in direct sunlight.

Best Mobile Processor

The processor in your mobile device determines how fast your apps will run. Today’s best mobile devices have multi-core processors, which allow your device to do several things at once without slowing down. More info.

The Asus Transformer Prime was the first quad-core powered mobile device

  • First place: The ASUS Transformer Prime has an NVIDIA Tegra 3 quad-core processor which out performs every mobile device on the market today in most benchmarks.
  • Runner-up: The HTC Rezound, LG Nitro HD and Samsung Galaxy S II Skyrocket all have 1.5GHz dual-core processors. The HTC Jetstream tablet also has a 1.5GHz dual-core processor.
  • What to look for: Quite a few quad-core smartphones will be announced in Q1. Dual-core CPUs in smartphones will hit speeds of 1.8 GHz in 2012. Tablet processors will hit speeds of 2GHz in 2012, and could go as high as 2.5GHz.

Fastest Data Speeds

4G LTE devices are at least 5-10x faster than 3G devices

Data speeds have a significant impact on the perceived speed of your mobile device. Verizon claims 4G LTE speeds that are at least twice as fast as AT&T’s 4G HSPA+ phones and up to 12 times faster than 3G speeds. More info.

  • First place: LTE phones like the Samsung Galaxy Nexus and Galaxy S II HD LTE win because they work on LTE networks and support both 2.5GHz and 5.0GHz Wi-Fi.
  • Runner-up: The HTC Rezound, Motorola Droid RAZR, Motorola Xoom, Samsung Galaxy Tab 10.1, HTC  Jetstream and all other mobile devices which support LTE or WiMAX.
  • What to look for: Expect Apple’s iPhone to finally get LTE support in 2012.

Best Camera

Today’s best mobile devices have 8 megapixel rear cameras which are capable of taking surprisingly good-looking photos. Most have LED flashes and front-facing cameras for video conferencing.

The HTC Titan II will be the first phone with a 16MP camera

  • First place: Too close to call. The 12MP Nokia N8 wins on specs with its Carl Zeiss optics and a xenon flash, but it’s on a Symbian phone which is more than a year old. When it comes to smartphones with 8MP cameras, the iPhone 4S, HTC Amaze, HTC Sensation, HTC Titan, Samsung Galaxy S II and T-Mobile MyTouch Slide all take photos which rival some point-and-shoot cameras. The Samsung Galaxy 10.1V tablet comes in first because of its 8MP camera. Unfortunately, this model is only available in Europe.
  • Runner-up: The Samsung Galaxy Nexus has a stellar light sensor and almost no shutter lag when taking photos in rapid succession. The BlackBerry PlayBook and HTC Flyer also deserve recognition because they have 3-MP front-facing cameras.
  • What to look for: The HTC Titan II will be released in March with the first 16-megapixel camera! Fujitsu is also releasing a 13.1MP camera capable of ISO 25,600. Expect to see a camera with a xenon flash and optical zoom later this year as well. Future tablets will also be capable of 1440p video playback.

Most Internal Storage

The Archos 70 has 250GB of storage

Today most mobile devices have only 16 or 32 MB of internal storage. Unfortunately that is not enough storage for a large media library.

  • First place: The Archos 70 tablet has an internal 250GB hard drive.
  • Runner-up:  The Apple iPhone 4S, Nokia N8 and Nokia N9 are all available with 64GB of internal storage.
  • What to look for:  Expect to see more tablets which have lightning-fast solid-state drives like the Asus Eee Slate.

Most Powerful Battery

Today’s fastest mobile devices require more power than ever. Especially those with high processor speeds and power-hungry LTE radios. That’s why we’re seeing mobile devices with more powerful batteries.

The HTC Jetstream has a 7300 mAh battery

  • First place: The HTC Jetstream has a 7300 mAh battery, which is the most powerful battery available in a stock mobile device today.
  • Runner-up:  Samsung Galaxy Tab 10.1 (7000 mAh). The Droid RAZR Maxx has the most powerful battery in a smartphone today. At 3300mAh, this phone has a talk time of 21.5 hours and a standby time of approx. 15.8 days.
  • What to look for in the near future:  Expect to see even more powerful batteries in mobile devices, and the ability to add a second battery to some tablets.

Thinnest Case

Today’s best mobile devices are incredibly thin and light.

The Droid Razr is the World's Thinnest LTE Smartphone

  • First place: The 6.68mm Huawei Ascend P1S is technically now the world’s thinnest smartphone. It’s effectively tied with the Fujitsu Arrows F-07D which comes in at 6.7mm. Too bad neither phone is available in the U.S. and both don’t support LTE. The 7.1mm Motorola Droid RAZR is the thinnest LTE smartphone. The 7.0mm OGT Eros is supposed to be the world’s thinnest tablet but it has yet to be released.
  • Runner-up:  The 8.3 mm ASUS Transformer Prime is the thinnest tablet available in the U.S today.
  • What to look for in future cases:  Expect to see more mobile devices which can be submerged in water. Fujitsu’s new quad-core phone can be submerged 1.5 meters for up to 30 minutes.

The Final Word

It’s a given that technology will always get better over time, but we’ve seen unprecedented improvements in mobile devices over the past year. Today’s best smartphones blow away some of those which were released earlier. If you’re eligible for an upgrade, you should consider some of the devices covered in this article. As you can see, there isn’t a single mobile device that is best at everything. You should pick your next smartphone or tablet based on the things which matter most to you.

Update: Since this article was last updated, a chart listing the best smartphones was published here.

Copyright 2011-2012 Rick Schwartz. All rights reserved. Linking to this article is encouraged.