Galaxy Note OLED Display Technology Shoot-Out
Samsung Galaxy Note 4
Galaxy Note Edge
Dr. Raymond M. Soneira
President, DisplayMate Technologies Corporation
Results Highlights
In this Results section we provide Highlights of the comprehensive DisplayMate Lab tests and measurements and extensive visual comparisons using test photos, test images, and test patterns that are covered in the advanced sections. The main Display Shoot-Out Comparison Table summarizes the Galaxy Note 4 Lab measurements in the following categories: Screen Reflections, Brightness and Contrast, Colors and Intensities, Viewing Angles, OLED Spectra, Display Power. You can also skip these Highlights and go directly to the Galaxy Note Edge Overview, and the Galaxy Note 4 Conclusions.
Systematically Improving OLED Displays
What is particularly significant and impressive is that Samsung has been systematically improving OLED display performance twice a year with each Galaxy generation since 2010. With the Galaxy Note 4 there are many significant improvements over the Galaxy Note 3 that we tested a year ago, but also with the Galaxy S5 that we tested in March, and Galaxy Tab S that we tested in June. The most impressive improvements for the Galaxy Note 4 are in the pixels per inch and resolution, the Absolute Color Accuracy, Peak Brightness and screen viewability in High Ambient Light, and display Power Efficiency, which we discuss in turn below.
2.5K Quad HD 2560x1440 Display
The Galaxy Note 4 has a Quad HD 2560x1440 pixel display, currently the highest resolution for Smartphones, with 3.7 Mega Pixels, almost double the number on your HDTV. It provides lots of image detail – it can display four complete HD 1280x720 images at once. The display has Diamond Pixels (see below) and Sub-Pixel Rendering with 518 pixels per inch (ppi), providing significantly higher image sharpness than can be resolved with normal 20/20 Vision at the typical viewing distances of 10 inches or more for Smartphones, so the display appears perfectly sharp. The Galaxy Note 3 and Galaxy S5 both have very respectable Full HD 1920x1080 displays with 2.1 Mega Pixels. At typical viewing distances they also appear perfectly sharp for 20/20 Vision.
However, there are some significant advantages in going higher than the visual acuity for 20/20 Vision at typical viewing distances. For Smartphones they include a closer match to digital photo resolutions, the ability to display Full HD 1920x1080 images with an additional 1.6 Mega Pixels left over for displaying additional content at the same time, plus efficient and simple rescaling (with small integer ratios) of various HD and Quad screen resolution formats to improve processing efficiency and resulting picture quality.
In addition, if you really want (or need) to take advantage of the extra fine display sharpness and resolution above normal 20/20 Vision, you can. If you study and stare at the image on the screen, move it closer and move it around, you’ll be able to make out considerably more fine image detail because you are building an integrated visual map of the image in your brain. So, when you are looking at an image with very finely detailed graphics and small text, most people with reasonably good vision will be able to make out and take advantage of the extra sharpness and image detail if they take the time to do so. See our 2014 Innovative Displays and Display Technology article for more details.
Multiple Screen Modes and Color Management
Most Smartphones and Tablets only provide a single fixed factory display Color Gamut and color calibration, with no way for the user to alter it based on personal preferences, running applications, or Ambient Light levels. An important capability provided by the OLED Galaxy Smartphones and the new Galaxy Tab S Tablets is the implementation of Color Management that provides a number of Screen Modes, each with different Color Gamuts and levels of user selectable color saturation and display calibration based on user and application preferences. Color Management with multiple and varying Color Gamuts are a very useful and important state-of-the-art capability that all displays will need to provide in the future. The Galaxy Note 4 has four user selectable Screen Modes: Adaptive Display, AMOLED Photo, AMOLED Cinema, and the Basic Screen Mode, which matches the Standard sRGB/Rec.709 Color Gamut that is used for virtually all current consumer content. See this Figure for the Color Gamuts of the different tested Screen Modes and the Colors and Intensities section for measurements and details. We discuss each of the tested Screen Modes next…
Adaptive Display Mode with a Wide Color Gamut
The Adaptive Display screen mode provides real-time adaptive processing to dynamically adjust images and videos – for some applications it will vary the White Point, Color Gamut, and Color Saturation based on the image content and the color of the surrounding ambient lighting measured by the Ambient Light Sensor (which measures color in addition to brightness). The Adaptive Display mode also delivers significantly higher color saturation, with 130 percent of the Standard sRGB/Rec.709 Color Gamut, among the highest that we have ever measured for Smartphones and Tablets. Some people like the extra saturated vibrant colors, plus it is useful for special applications, and for viewing the display in medium to high levels of ambient light, because it offsets some of the reflected light glare that washes out the on-screen image colors.
AMOLED Photo Mode with an Adobe RGB Color Gamut
Most high-end digital cameras have an option to use the Adobe RGB Color Gamut, which is 17 percent larger than the Standard sRGB/Rec.709 Color Gamut used in consumer cameras. The AMOLED Photo screen mode on the Galaxy Note 4 provides a very accurate calibration to the Adobe RGB standard, which is rarely available in consumers displays, and is very useful for high-end digital photography and other advanced imaging applications. The measured Absolute Color Accuracy of the AMOLED Photo screen mode for the Galaxy Note 4 is 1.6 JNCD, which is impressively accurate. See this Figure for an explanation and visual definition of JNCD and the Color Accuracy Plots showing the measured display Color Errors. There are very few consumer displays that can accurately reproduce Adobe RGB, so this is a significant plus for serious photography enthusiasts. See the Color Accuracy section and the Color Accuracy Plots for measurements and details.
Basic Mode with the Standard sRGB / Rec.709 Color Gamut
The Basic screen mode provides a very accurate Color and White Point calibration for the Standard sRGB/Rec.709 Color Gamut that is used in virtually all current consumer content for digital cameras, HDTVs, the internet, and computers, including photos, videos, and movies. The Color Gamut of the Basic screen mode is very accurate, with a nearly perfect 101 percent of the Standard sRGB/Rec.709 Color Gamut. Even better, the Absolute Color Accuracy for the Basic screen mode is an impressive 1.5 JNCD, the most color accurate display that we have ever measured for a Smartphone or Tablet, which is visually indistinguishable from perfect, and is very likely considerably better than your living room TV. See this Figure for an explanation and visual definition of JNCD and the Color Accuracy Plots showing the measured display Color Errors, and also this regarding Bogus Color Accuracy Measurements.
Use the Basic screen mode for the best color and image accuracy, which is especially important when viewing photos from family and friends (because you often know exactly what they actually should look like), for some TV shows, movies, and sporting events with image content and colors that you are familiar with, and also for viewing online merchandise, so you have a very good idea of exactly what colors you are buying and are less likely to return them. See the Color Accuracy section and the Color Accuracy Plots for measurements and details.
Screen Brightness and Performance in High Ambient Lighting
Mobile displays are often used under relatively bright ambient light, which washes out the image colors and contrast, reducing picture quality and making it harder to view or read the screen. To be usable in high ambient light a display needs a dual combination of high screen Brightness and low screen Reflectance – the Galaxy Note 4 has both. For most image content the Galaxy Note 4 provides over 400 cd/m2 (Luminance, which is a measure of Brightness sometimes called nits), comparable or higher than most LCD displays in this size class. Its Screen Reflectance is 4.8 percent, close to the lowest that we have ever measured. Our Contrast Rating for High Ambient Light quantitatively measures screen visibility under bright Ambient Light – the higher the better. As a result of its high Brightness and low Reflectance, the Galaxy Note 4 has a Contrast Rating for High Ambient Light that ranges from 71 to 93, among the highest that we have ever measured.
More importantly, on the Galaxy Note 4 the Maximum Brightness can go much higher when Automatic Brightness is turned On, so that users can’t permanently park the Manual Brightness slider to very high values, which would run down the battery quickly. High screen Brightness is only needed for High Ambient Light, so turning Automatic Brightness On will provide better high ambient light screen visibility and also longer battery running time.
When Automatic Brightness is turned On, the Galaxy Note 4 reaches an impressive 750 cd/m2 in High Ambient Light, where high Brightness is really needed – it is the brightest mobile display that we have ever tested. As a result of its high Brightness and low Reflectance, the Galaxy Note 4 has a Contrast Rating for High Ambient Light that ranges from 100 to156, the highest that we have ever measured for any mobile display. See the Brightness and Contrast, the High Ambient Light and the Screen Reflections sections for measurements and details.
Super Dimming Mode
The Galaxy Note 4 also has a Super Dimming Mode that allows the Maximum Screen Brightness to be set all the way down to just 2 cd/m2 (nits) using the Brightness Slider. This is useful for working comfortably without eye strain or bothering others in very dark environments, or affecting the eye’s dark adaptation, such as when using a telescope. The display still delivers full 24-bit color and the picture quality remains excellent.
Diamond Pixels
A high resolution screen shot (provided by Samsung) shows an interesting design and sub-pixel arrangement for the Galaxy Note 4, which Samsung calls Diamond Pixels. First of all, the Red, Green, and Blue sub-pixels have very different sizes – Blue is by far the largest because it has the lowest efficiency, and Green is by far the smallest because it has the highest efficiency. The alternating Red and Blue sub-pixel arrangement leads to a 45 degree diagonal symmetry in the sub-pixel layout. This allows vertical, horizontal, and particularly diagonal line segments and vectors to be drawn with reduced aliasing and artifacts. In order to maximize the sub-pixel packing and achieve the highest possible pixels per inch (ppi), that leads to diamond rather than square or stripe shaped Red and Blue sub-pixels. But not for the Green sub-pixels, which are oval shaped because they are squeezed between two much larger and different sized Red and Blue sub-pixels. It’s a form of high-tech display art…
Display Power Efficiency
With each successive generation Samsung has been systematically improving the power efficiency of their OLED displays. We measured a 14 percent improvement in display power efficiency between the Galaxy Note 3 and the Note 4, which is especially impressive given that the Note 4 has almost double the number of pixels and therefore much higher processing overhead. The Galaxy Note 4 also has an Ultra Power Saving Mode that lowers the Screen Brightness and also sets the background to Black, both of which significantly reduce display power and can double the running time on battery. See the Display Power section for measurements and details.
Viewing Angle Performance
While Smartphones are primarily single viewer devices, the variation in display performance with viewing angle is still very important because single viewers frequently hold the display at a variety of viewing angles. The angle is often up to 30 degrees, more if it is resting on a table or desk. While LCDs typically experience a 55 percent or greater decrease in Brightness at a 30 degree Viewing Angle, the OLED Galaxy Note 4 display shows a much smaller 19 percent decrease in Brightness at 30 degrees. This also applies to multiple side-by-side viewers as well, and is a significant advantage of OLED displays. The Color Shifts with Viewing Angle are also relatively small. See the Viewing Angles section for measurements and details.
Viewing Tests
The Galaxy Note 4 Basic screen mode provides very nice, pleasing and accurate colors, and picture quality. Although the Image Contrast is slightly too high (due to a slightly too steep Intensity Scale), the very challenging set of DisplayMate Test and Calibration Photos that we use to evaluate picture quality looked Beautiful, even to my experienced hyper-critical eyes. The Basic screen mode is recommended for indoor and low ambient light viewing of most standard consumer content for digital camera, HDTV, internet, and computer content, including photos, videos, and movies. The Adaptive Display screen mode has significantly more vibrant and saturated colors. Some people like that. It is also recommended for viewing in medium to high levels of ambient light because it offsets some of the reflected light glare that washes out the images.
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