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Surface RT Display Technology Shoot-Out

Microsoft Surface RT  –  Apple iPad 3  –  Samsung Galaxy Tab 10.1

 

Dr. Raymond M. Soneira

President, DisplayMate Technologies Corporation

 

Copyright © 1990-2012 by DisplayMate Technologies Corporation. All Rights Reserved.

This article, or any part thereof, may not be copied, reproduced, mirrored, distributed or incorporated

into any other work without the prior written permission of DisplayMate Technologies Corporation

 

 

Microsoft Surface RT

Introduction

The new Windows Tablets, led by Microsoft’s Surface, provide a third major family of Tablets for consumers and the computing world. The significance and stakes are enormous because Tablets are among the most important developments in computing and consumer products in the last 20 years. Like Google's Android Tablets, the Windows Tablets will be made by many different manufacturers. And just like Google’s Nexus, which provides reference designs for the Android product line, Microsoft is producing its own Surface Tablets for the Windows product line.

 

With large numbers of Tablets and Smartphones running virtually identical software, the display becomes the single most important way for manufacturers to differentiate their products – that’s been true for Android and the same will apply for Windows devices. A top notch display makes everything that runs on a Tablet or Smartphone look great or as good as possible – including all of the Apps, web content, photos, and videos – looking a lot better than on devices with inferior displays. The inferior displays will be either cheap low-end displays, or expensive displays manufactured with bad parameter choices, or high quality displays ruined through improper calibration at the factory. It will be interesting to see which manufacturers play for the top, and those that try to get away with playing the bottom…

 

The Microsoft Surface and all Windows Tablets are coming in two versions: the just launched Windows RT with a 1366x768 display that we test here, and the Windows Pro Tablets with a 1920x1080 display that will launch in early 2013. In this Display Shoot-Out we’ll tell you all about the Microsoft Surface display with extensive Lab measurements, viewing tests, and objective in-depth analysis. For other aspects including its OS, Apps, and overall operation and functionality you'll need to refer to reviews that cover these issues in detail but generally provide little information about the display.

 

The Shoot-Out

To examine the performance of the Microsoft Surface RT we ran our in-depth series of Mobile Display Technology Shoot-Out tests and compared it to Apple iPad 3 and the Samsung Galaxy Tab 10.1. The Galaxy Tab 10.1 was chosen for this Shoot-Out because it has the best display performance for the standard resolution 10 inch Android Tablets in our Display Shoot-Out series. The Apple iPad 2 is also included in the comparisons.

 

We take display quality very seriously and provide in-depth objective analysis side-by-side comparisons based on detailed laboratory measurements and extensive viewing tests with both test patterns and test images. For additional background and information see the iPad Display Technology Shoot-Out article that compares the iPad 2 and the new iPad 3, the 10 Inch Tablet Display Technology Shoot-Out that compares 5 “popular” full size Tablets, and the 7 Inch Tablet Display Technology Shoot-Out that compares the Amazon Kindle Fire HD and the Google Nexus 7.

 

Results Highlights

In this Results section we provide Highlights of the comprehensive lab measurements and extensive side-by-side visual comparisons using test photos, test images and test patterns that are presented in later sections. The Comparison Table in the following section summarizes the Lab measurements in the following categories:  Screen ReflectionsBrightness and ContrastColors and IntensitiesViewing AnglesDisplay Backlight Power ConsumptionRunning Time on Battery. You can also skip the Highlights and go directly to the Conclusions.

 

Sharpness and Resolution:

The Surface RT screen resolution of 1366x768 pixels is comparable to most existing Tablets, but many of the latest Tablets have been launching at 1920x1080 or above, which provides double the total number of pixels, and 50 percent greater Pixels Per Inch, or more. Specs aside, what is the actual visual significance of the lower pixel count? Most consumers are unlikely to notice much of a visual difference in photos and videos because they are inherently fuzzy – it’s really only critical for providing visually sharp text.

 

The Surface RT uses Sub-Pixel Rendering (called ClearType in Microsoft’s implementation) that in our tests significantly improves the visual sharpness of text over standard Pixel Rendering that is used in most mobile displays. In our comparison tests, text on the Surface RT was significantly sharper than on the iPad 2 and all 1280x800 10 inch Android Tablets, but it wasn’t as sharp as the iPad 3.

 

Screen Reflectance:

The screens on almost all Tablets and Smartphones are mirrors good enough to use for personal grooming. Even in moderate ambient lighting the image contrast and colors can noticeably degrade from ambient light reflected by the screen, washing out the images and colors and producing distracting mirror reflections superimposed on the screen. So low Reflectance is extremely important in determining real world picture quality. The lower the better…

 

Our Lab measurements found the Surface RT to have the lowest Screen Reflectance of any Tablet in our Display Shoot-Out article series. The Surface RT also has the highest Contrast Rating for High Ambient Light for Tablets, which quantitatively measures screen visibility under bright ambient lighting – the higher the better… This article has screen shots that show how screen images degrade in High Ambient Lighting.

 

Color Gamut and Color Accuracy:

While the display Pixels Per Inch and pixel Resolution seem to get most of the attention, it is the display’s Color Gamut together with the Factory Display Calibration (below) that play the most important role in determining the Wow factor and true picture quality and color accuracy of a display. The Color Gamut is the range of colors that a display can produce. If you want to see accurate colors in photos, videos, and all standard consumer content the display needs to closely match the Standard Color Gamut that was used to produce the content, which is called sRGB / Rec.709. Most of the existing LCD Tablets and Smartphones have smaller Color Gamuts around 60 percent of the Standard Gamut, which produces somewhat subdued colors. The main reason for providing a smaller Color Gamut is to improve screen Brightness, Power Efficiency, and Battery Running Time, which is important for many users.

 

The Surface RT has a smaller 57 percent Color Gamut, which is disappointing in an otherwise excellent set of display performance specifications. While that‘s comparable to most existing LCDs in Tablets and Smartphones, many mobile displays are now coming with larger Color Gamuts from 80 to 100 percent, which significantly improves color saturation, accuracy, and vividness.

 

Factory Display Calibration:

The raw LCD panel hardware first needs to be adjusted and calibrated at the factory with specialized firmware and software data that are downloaded into the device in order for the display to produce a usable image – let alone an accurate and beautiful one. This is actually a science but most manufacturers seem to treat it as if it were a modern art form, so few Tablets, Smartphones, and even HDTVs produce accurate high quality images.

 

Microsoft has paid careful attention to factory display calibration unlike most other manufacturers – including most of the Android and Nexus devices that we have tested. The Surface RT has an accurate White Point and an accurate Intensity Scale, which are both very important for accurate image reproduction. Apple has been a leader in accurate display calibration, but all of the iPads and iPhones that we have tested have White Points that are slightly too blue, which can impart a cold or bluish caste to some images – such as in shifting the complexions of faces slightly.

 

Viewing Tests:

Using our extensive library of challenging test and calibration photos, we compared the Surface RT to a calibrated professional studio monitor and to the new iPad 3, which has a virtually perfect Factory Calibration and Color Gamut.

 

Images on the Surface RT were accurate with good contrast, but with somewhat subdued colors like most existing Tablets and Smartphones due to its smaller Color Gamut. As a result, the Surface RT display was unable to produce very saturated colors, like fire engine red, which was not as vibrant and appeared with a noticeable shift towards orange. Very saturated purples are also especially difficult to reproduce on LCD displays with a reduced color Gamut. For example, the Surface RT appeared almost identical to the iPad 2 in this screen shot comparing the iPad 2 to the new iPad 3.

 

 

Conclusions for the Microsoft Surface RT Display

The display on the Microsoft Surface RT outperforms all of the standard resolution full size 10 inch Tablets that we have tested in our Display Shoot-Out series. The Lab tests and measurements documented in the Shoot-Out Comparison Table below indicate that Microsoft has paid a lot of attention to display performance for the Surface RT. In particular, on-screen text is significantly sharper, it has a better factory display calibration, and also significantly lower screen Reflectance than the iPad 2 and all full size 1280x800 Android Tablets. But it is not as sharp as the iPad 3 or 4, nor does it have their large full Color Gamut. We’ll have to wait for the high resolution Windows Pro Tablets that will be launching in early 2013 for direct comparisons with the high resolution iPads and Android Tablets. This is a great start for Windows Tablets and brings much needed competition to the Tablet marketplace. In addition, many other manufacturers will be launching their own branded Windows RT and Pro Tablets – we’ll include the best of them in future Mobile Display Shoot-Outs.

 

Before we discuss the comparisons with the Apple iPads and Android Tablets we’ll first discuss the principal issues for the Surface RT display. The test and measurement details are provided in the Comparison Table below.

 

Screen Resolution

The 1366x768 Surface RT screen resolution has been the source for lots of discussions. While it’s comparable to most existing Tablets, many of the latest Tablets have been launching at 1920x1080 or above, which provide double the total number of pixels, and 50 percent greater Pixels Per Inch, or more. Specs aside, what is the actual visual significance of the lower pixel count? While most consumers are unlikely to notice much of a visual difference in photos and videos because they are inherently fuzzy, where the higher pixel counts can make a big difference is with small text and fine graphics.

 

Enhanced Screen Sharpness

While Screen Resolution gets lots of attention from both consumers and marketers – it’s really only critical for providing visually sharp text – but that applies for most applications running on a Tablet. As we have pointed out a number of times, the best way to increase text visual sharpness on any display is by using Sub-Pixel Rendering (performed in software). Surface RT and all Windows displays use Sub-Pixel Rendering (called ClearType in Microsoft’s implementation) that in our tests significantly improved the visual sharpness of text over standard Pixel Rendering that is used in most mobile displays – see the comparisons below. Finally, if the lower Screen Resolution spec is an issue, simply wait for the Surface Pro and Window Pro Tablets with 1920x1080 resolution that will launch in early 2013. With their ClearType Sub-Pixel Rendering they should provide visual text sharpness that is comparable to the highest resolution Tablet displays being introduced.

 

Low Screen Reflectance

Low Screen Reflectance is very important because Tablets are almost never viewed in the dark, so screen reflections often significantly degrade image quality, color accuracy, and screen readability – washing out the images and colors and producing distracting mirror reflections superimposed on the screen. As a result, low Screen Reflectance is extremely important for real world visual display performance and image quality. It also allows the display to run with lower Screen Brightness settings, which extends the Battery Running Time. Our Lab measurements found the Surface RT to have the lowest Screen Reflectance of any Tablet in our Display Shoot-Out article series. For comparison, the iPad 3 reflects 33 percent more Ambient Light than the Surface RT and the Galaxy Tab 10.1 reflects 41 percent more. Mirror Reflections are 52 percent and 62 percent brighter than the Surface RT. The Surface RT also has the highest Contrast Rating for High Ambient Light for Tablets, which quantitatively measures screen visibility under bright ambient lighting – the higher the better… This article has screen shots that show how screen images degrade in High Ambient Lighting.

 

Smaller Color Gamut

The Surface RT has a smaller 57 percent Color Gamut, which is disappointing in an otherwise excellent set of display performance specifications. While that‘s comparable to most existing LCDs in Tablets and Smartphones, many mobile displays are now coming with larger Color Gamuts from 80 to 100 percent of the sRGB / Rec.709 Standard, which significantly improves color saturation, accuracy, and vividness. The subdued colors were quite apparent in our photo comparison tests. The main reason for providing a smaller Color Gamut is to improve screen Brightness, Power Efficiency, and Battery Running Time. In that regard, the Surface RT has the second longest Battery Running Time at Maximum Brightness for any Tablet that we have tested – for many users that will be considered a good strategic tradeoff.

 

Comparisons with the Android Tablets

The Surface RT out performs the displays on all of the full size 10 inch 1280x800 Android Tablets that we have tested. However, the 7 inch Amazon Kindle Fire HD and Google Nexus 7 have a larger 86 percent Color Gamut and much higher Pixels Per Inch screens. In terms of visual sharpness, the Surface RT with ClearType Sub-Pixel Rendering improves text sharpness significantly so that it is significantly sharper than the Galaxy Tab 10.1 and other 10 inch 1280x800 Tablets, but not quite as sharp as the 7 inch Kindle Fire HD and Nexus 7 in our visual comparison tests. The Kindle Fire HD has a very good factory calibration like the Surface RT (but the Nexus 7 does not). We’ll compare the 1920x1200 Android Tablets with the 1920x1080 Surface Pro in a future Display Shoot-Out. For details see the 10 Inch Tablet Display Technology Shoot-Out and the 7 Inch Tablet Display Technology Shoot-Out.

 

Comparisons with the Apple iPads

The Surface RT out performs the display on the iPad 2 across the board except for the Color Gamut. The Surface RT is comparable or better than the iPad 3 in all test categories except two: Screen Resolution and Color Gamut. The iPad 3 has a much higher resolution of 2048x1536 and a much larger 99 percent Color Gamut. In terms of visual sharpness, the Surface RT with ClearType Sub-Pixel Rendering improves text sharpness significantly so that it is significantly sharper than the iPad 2, but not as sharp as the iPad 3. In terms of the Color Gamut, the new iPad 3 has significantly better color saturation and color accuracy. While the Surface RT Color Gamut is similar to the iPad 2, the iPad 2 has somewhat better color saturation because of its steeper Intensity Scale and Gamma (as explained in Figure 3 below). For details see the new iPad 3 and iPad 2 Display Technology Shoot-Out.

 

The Next Generation of Tablet Displays

See our new iPad Shoot-Out Conclusion for a discussion of the many improvements that are needed for the next generation of Tablet displays.

 

 

DisplayMate Display Optimization Technology

All Tablet and Smartphone displays can be significantly improved using DisplayMate’s advanced scientific analysis and mathematical display modeling and optimization of the display hardware, factory calibration, and driver parameters. We help manufacturers with expert display procurement and quality control so they don’t make mistakes similar to those that are exposed in our Display Technology Shoot-Out article series. We can also improve the performance of any specified set of display parameters. This article is a lite version of our intensive scientific analysis – before the benefits of our DisplayMate Display Optimization Technology, which can correct or improve all of these issues. If you are a display or product manufacturer and want to significantly improve display performance for a competitive advantage then Contact DisplayMate Technologies.

Samsung Galaxy Tab 10.1

Microsoft Surface RT

Apple new iPad 3

 

Display Shoot-Out Comparison Table

Below we compare the display on the Microsoft Surface RT to the Apple iPad 3 and the Samsung Galaxy Tab 10.1 based on objective measurement data and criteria. We also include some comparisons with the Apple iPad 2. The Samsung Galaxy Tab 10.1 was chosen because it has the best display performance for the standard resolution 10 inch Android Tablets in our Display Shoot-Out series. Note that the Tablets were all purchased independently by DisplayMate Technologies through standard retail channels.

 

For additional background and information see the iPad Display Technology Shoot-Out article that compares the iPad 2 and the new iPad 3, the 10 Inch Tablet Display Technology Shoot-Out that compares 5 “popular” full size Tablets, and the 7 Inch Tablet Display Technology Shoot-Out that compares the Amazon Kindle Fire HD and the Google Nexus 7.

 

Categories

Samsung

Galaxy Tab 10.1

Microsoft

Surface RT

Apple

new iPad 3

Comments

Screen Diagonal Size

Display Technology

10.1 inch

PLS LCD

10.6 inch

PLS LCD

9.7 inch

IPS LCD

Liquid Crystal Display

Plane to Line Switching  or  In Plane Switching

IPS and PLS LCDs have wide viewing angles.

Screen Shape

16:10  =  1.60

Aspect Ratio

16:9  =  1.78

Aspect Ratio

4:3  =  1.33

Aspect Ratio

The Surface screen has the same shape as HDTVs.

The iPad screen has the same shape as 8.5x11 paper.

Screen Area

45.8 Square Inches

48.0 Square Inches

45.2 Square Inches

A better measure of size than the diagonal length.

Relative Screen Area

95 percent

100 percent

94 percent

Screen Area relative to the Surface RT.

Display Resolution

1280 x 800 pixels

1366 x 768 pixels

2048 x 1536 pixels

The more Pixels and Sub-Pixels the better.

Active Display Area

1280 x 752 pixels

1366 x 768 pixels

2048 x 1536 pixels

The Galaxy Tab reserves 48 pixels for a navigation bar.

Pixels Per Inch

149 ppi

Good

148 ppi

Good

264 ppi

Excellent

At 12 inches from the screen 20/20 vision is 286 ppi.

See this on the visual acuity for a true Retina Display

20/20 Vision Retina Display

down to this Viewing Distance

20/20 “Retina Display”

to 23 inches Viewing

20/20 “Retina Display”

to 23 inches Viewing

20/20 “Retina Display”

to 13 inches Viewing

For 20/20 Vision the minimum Viewing Distance

where the screen appears perfectly sharp to the eye.

Pixels Per Square millimeter

34 ppmm2

34 ppmm2

108 ppmm2

Image elements like text letters are seen as

2D objects drawn as a small area of pixels.

Sub-Pixel Rendering

Improves Sharpness

No

Pixel Rendering

Yes

 Text and Graphics

No

Pixel Rendering

Sub-Pixel Rendering improves visual image

sharpness for Text and Graphics.

Small Text Readability

Somewhat Fuzzy

Reasonably Good

Excellent

Perceived visual sharpness reading small text such

as on The New York Times website front page.

Gallery / Photo Viewer Color Depth

Full 24-bit color

No Dithering Visible

256 Intensity Levels

Full 24-bit color

No Dithering Visible

256 Intensity Levels

Full 24-bit color

No Dithering Visible

256 Intensity Levels

Many Android Tablets and Smartphones still have some

form of 16-bit color depth in the Gallery Photo Viewer

 

Galaxy Tab 10.1

Surface RT

new iPad 3

 

 

Overall Assessments

This section summarizes the results of all of the extensive Lab measurements and viewing tests performed on all of the displays.

 

Viewing Tests

Good Images

Photos and Videos

have too much color

and too much contrast

Good Images

Photos and Videos

have too little color

and accurate contrast

Very Good Images

Photos and Videos

have accurate color

and accurate contrast

The Viewing Tests examined the accuracy of

photographic images by comparing the displays

to a calibrated studio monitor and HDTV.

Variation with Viewing Angle

Small Color Shifts

with Viewing Angle

 

Large Brightness Shift

with Viewing Angle

Small Color Shifts

with Viewing Angle

 

Large Brightness Shift

with Viewing Angle

Small Color Shifts

with Viewing Angle

 

Large Brightness Shift

with Viewing Angle

IPS and PLS LCDs have Small Color Shifts.

TN LCDs have Large Color Shifts.

 

All LCDs have Large Brightness Shifts

Viewing the Screen with

Polarized Sunglasses

No Extinction

 

View Any Orientation

No Extinction

 

View Any Orientation

Portrait Extinction

 

View in Landscape

Polarized Sunglasses are increasingly popular,

which often makes the screen invisible black for

certain orientations.

Overall Display Assessment

Lab Tests and Viewing Tests

Very Good Display

Good Calibration

Very Good Display

Very Good Calibration

Excellent Display

Excellent Calibration

Lab and Viewing Test Assessments

Major Display Weaknesses

Higher Reflectance

Smaller Color Gamut

Smaller Color Gamut

Higher Reflectance

Notable Display Weaknesses

Major Display Strengths

Brighter Display

Low Reflectance

Sub-Pixel Rendering

Accurate Color Gamut

Very Sharp Display

Notable Display Strengths

Current Overall Display Grade

Good  B+

 Very Good  A–

Excellent  A

Our Overall Assessments based on all criteria

 

Galaxy Tab 10.1

Surface RT

new iPad 3

 

 

 

 

Screen Reflections

Figure 1.  Screen Reflection Photos

Click to Enlarge

All of these screens are large mirrors good enough to use for personal grooming – but it’s actually a very bad feature…

We measured the light reflected from all directions and also direct mirror (specular) reflections, which are much more

distracting and cause more eye strain. The 10 – 15 percent reflections can make the screen much harder to read even

in moderate ambient light levels, requiring ever higher brightness settings that waste precious battery power. Hopefully

manufacturers will reduce the mirror reflections with anti-reflection coatings and haze surface finishes.

 

Low Screen Reflectance is extremely important because the Tablets are generally viewed in moderate to high Ambient Lighting.

Screen readability, picture quality, color accuracy, and gray scale accuracy are all adversely affected by reflections.

As a result screen Reflectance is much more important than Black Level and Contrast Ratio, and even Screen Brightness.

 

The Surface RT has the lowest Reflectance we have measured for all of the Tablets in our Display Shoot-Outs.

The iPad 3 reflects 33 percent more Ambient Light than the Surface RT and the Galaxy Tab 10.1 reflects 41 percent more.

The iPad 3 has 52 percent brighter Mirror Reflections than the Surface RT and the Galaxy Tab 10.1 has 62 percent more.

Cover Glass

with Air Gap or Bonded to Display

See Figure 1

Cover Glass Bonded

No Air Gap

Cover Glass Bonded

No Air Gap

Air Gap

A Cover Glass with an Air Gap is easier to

manufacture. Optical Bonding reduces both

external and internal Reflections. See Figure 1

Average Screen Reflections

Percentage of Reflected

Light From All Directions

Reflects 8.2 percent

Good

Reflects 5.8 percent

Very Good

Reflects 7.7 percent

Very Good

Measured using an Integrating Hemisphere that

produces a uniform anisotropic light distribution.

Specular Mirror Reflections

Percentage of Light Reflected

See Figure 1

Reflects 10.5 percent

Poor

Reflects 6.5 percent

Very Good

Reflects 9.9 percent

Good

These are the most annoying types of reflections.

Measured using a narrow collimated pencil beam of

light reflected off the screen. See Figure 1

 

Galaxy Tab 10.1

Surface RT

new iPad 3

 

 

Brightness and Contrast

The Contrast Ratio is the specification that gets the most attention, but it only applies for low ambient light, which is seldom

the case for mobile displays. Much more important is the Contrast Rating, which indicates how easy it is to read the screen

under high ambient lighting and depends on both the Maximum Brightness and the Screen Reflectance.

 

All of the Tablets have comparable Brightness and Contrast Ratios, but Contrast Ratio is only relevant for low ambient light.

The Surface RT has the Best Contrast Rating for High Ambient Light for all of the Tablets in our Display Shoot-Outs.

Measured Maximum Brightness

is the Peak Luminance for White

Brightness 464 cd/m2

Very Good

Brightness 428 cd/m2

Very Good

Brightness 421 cd/m2

Very Good

Maximum Brightness is very important for mobile

because of the typically high ambient light levels.

Black Level

at Maximum Brightness

Black is 0.51 cd/m2

Very Good for Mobile

Black is 0.39 cd/m2

Very Good for Mobile

Black 0.48 cd/m2

Very Good for Mobile

Black brightness is important for low ambient light,

which is seldom the case for mobile devices.

Contrast Ratio

Relevant for Low Ambient Light

916

Very Good for Mobile

1,097

Very Good for Mobile

877

Very Good for Mobile

Measured in absolute darkness.

Only relevant for low ambient light.

Contrast Rating

for High Ambient Light

57

Good

74

Very Good

55

Good

Visual Contrast in High Ambient Lighting.

Defined as Maximum Brightness / Average Reflectance.

Screen Readability in Bright Light

Good    B+

Very Good    A–

Good    B+

Indicates how easy it is to read the screen

under high ambient lighting. Very Important!

See High Ambient Light Screen Shots

 

Galaxy Tab 10.1

Surface RT

new iPad 3

 

 

 

 

Colors and Intensities    

Figure 2.  Color Gamuts

Click to Enlarge

Figure 3.  Intensity Scales

Click to Enlarge

The Color Gamut, Intensity Scale, and White Point determine the quality and accuracy of all displayed images and all

the image colors. Bigger is definitely Not Better because the display needs to match all the standards that were used

when the content was produced. For LCDs a wider Color Gamut reduces the power efficiency and the Intensity Scale

affects both image brightness and color mixture accuracy.

 

The Surface RT is very well calibrated but its Color Gamut is at the low end of what we have seen in Tablets and Smartphones.

Some important issues regarding the Color Gamut are explained in Figure 2 and the Intensity Scale in Figure 3.

White Color Temperature

8,380 degrees Kelvin

White is Too Blue

6,571 degrees Kelvin

Close to Standard

7,085 degrees Kelvin

Somewhat Too Blue

D6500 is the standard color of White for most content

and necessary for accurate color reproduction.

Color Gamut

See Figure 2

64 percent of Std

Gamut Too Small

See Figure 2

57 percent of Std

Gamut Too Small

See Figure 2

99 percent of Std

Gamut Excellent

See Figure 2

sRGB / Rec.709 is the color standard for most

content and needed for accurate color reproduction.

Note that Too Large a Color Gamut is visually

worse than Too Small.

Dynamic Contrast or Backlight

None

Excellent

None

Excellent

None

Excellent

Many manufacturers manipulate the Intensity Scale

and Backlight based on image content. That results

in inaccurate colors and images.

Intensity Scale and Image Contrast

See Figure 3

Very Smooth But

Contrast is Too High

See Figure 3

Very Smooth

Contrast is Very Good

See Figure 3

Very Smooth

Contrast is Perfect

See Figure 3

The Intensity Scale controls Image Contrast needed

for accurate image reproduction. See Figure 3

Gamma for the Intensity Scale

Larger means more Image Contrast

See Figure 3

Good  2.32  –  2.77

Gamma Too High

Systematically Increases

Very Good  2.14

Gamma Slightly Low

Outstanding  2.20

Gamma is Perfect

Gamma is the slope of the Intensity Scale.

Gamma of 2.20 is the standard and needed for

accurate image reproduction. See Figure 3

 

Galaxy Tab 10.1

Surface RT

new iPad 3

 

 

Viewing Angles

The variation of Brightness, Contrast, and Color with viewing angle is especially important for Tablets because of

their large screen and multiple viewers. The typical manufacturer 176+ degree specification for LCD Viewing Angle

is nonsense because that is where the Contrast Ratio falls to a miniscule 10. For most LCDs there are substantial

degradations at less than ±30 degrees, which is not an atypical viewing angle for Tablets. IPS and PLS LCDs do well.

 

Note that the Viewing Angle performance is also very important for a single viewer because the Viewing Angle

varies based on how the Tablet is held, and the angle can be very large if the Tablet is resting on a table or desk.

All of these Tablets have LCDs that perform very well with similar Viewing Angle performance.

Brightness Decrease

at a 30 degree Viewing Angle

52 percent Decrease

Falls to 224 cd/m2

 

Very Large Decrease

 53 percent Decrease

Falls to 201 cd/m2

 

Very Large Decrease

 57 percent Decrease

Falls to 182 cd/m2

 

Very Large Decrease

Most screens become less bright when tilted.

 

LCD brightness variation is generally very large.

Contrast Ratio

at a 30 degree Viewing Angle

518

Very Good for Mobile

622

Very Good for Mobile

528

Very Good for Mobile

A measure of screen readability when the screen

is tilted under low ambient lighting.

Primary Color Shifts

at a 30 degree Viewing Angle

Small Color Shift

Δ(u’v’) = 0.0048

1.2 times JNCD

Small Color Shift

Δ(u’v’) = 0.0054

1.3 times JNCD

Small Color Shift

Δ(u’v’) = 0.0046

1.2 times JNCD

JNCD is a Just Noticeable Color Difference.

IPS and PLS LCDs have smaller color shifts.

Color Shifts for Color Mixtures

at a 30 degree Viewing Angle

Reference Brown (255, 128, 0)

Small Color Shift

Δ(u’v’) = 0.0034

0.8 times JNCD

Small Color Shift

Δ(u’v’) = 0.0056

1.4 times JNCD

Small Color Shift

Δ(u’v’) = 0.0073

1.8 times JNCD

JNCD is a Just Noticeable Color Difference.

 

Reference Brown is a good indicator of color shifts

with angle because of unequal drive levels and

roughly equal luminance contributions from

Red and Green.

 

Galaxy Tab 10.1

Surface RT

new iPad 3

 

 

Display Backlight Power Consumption

Figure 4.  LED Backlight Spectrum

Click to Enlarge

  

The Display Backlight power does not include the power used by the LCD itself or by the display electronics.

Since the displays have different screen sizes and maximum brightness, the values are also scaled to the

same screen brightness (Luminance) and screen area in order to compare their relative Power Efficiencies.

 

The Surface RT is significantly more Power Efficient than both the Galaxy Tab 10.1 and the new iPad 3.

This is consistent with its much longer Running Time on Battery, below.

Display Backlight Power

at Maximum Brightness

4.7 watts

2.3 watts

7.0 watts

Lower power consumption is important for energy

efficiency and improving running time on battery.

Display Backlight Power Efficiency

same Peak Luminance 428 cd/m2

same 10.6 inch screen size area

4.5 watts

2.3 watts

 7.6 watts

This compares the Relative Power Efficiency

by looking at the same screen brightness and

screen area.

 

Galaxy Tab 10.1

Surface RT

new iPad 3

 

 

Running Time on Battery

The running time on battery was determined with the Brightness sliders at Maximum, in Airplane Mode,

with no running applications, and with Auto Brightness turned off.

 

Note that Auto Brightness can have a considerable impact on running time but we found abysmal performance for

both the iPhone and Android Smartphones in our BrightnessGate analysis of Ambient Light Sensors and Automatic

Brightness. They all need a more convenient Manual Brightness Control as described in the BrightnessGate article.

 

The Surface RT has the second longest Battery Running Time at Maximum Brightness for any Tablet we have tested.

Since the display consumes the most device power, the Running Times at lower Brightness settings will be longer.

Running Time

At the Maximum Brightness Setting

4.8 hours

8.1 hours

5.8 hours

Display always On at the Maximum setting with

Airplane Mode and no running applications.

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Galaxy Tab 10.1

Surface RT

new iPad 3

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About the Author

Dr. Raymond Soneira is President of DisplayMate Technologies Corporation of Amherst, New Hampshire, which produces video calibration, evaluation, and diagnostic products for consumers, technicians, and manufacturers. See www.displaymate.com. He is a research scientist with a career that spans physics, computer science, and television system design. Dr. Soneira obtained his Ph.D. in Theoretical Physics from Princeton University, spent 5 years as a Long-Term Member of the world famous Institute for Advanced Study in Princeton, another 5 years as a Principal Investigator in the Computer Systems Research Laboratory at AT&T Bell Laboratories, and has also designed, tested, and installed color television broadcast equipment for the CBS Television Network Engineering and Development Department. He has authored over 35 research articles in scientific journals in physics and computer science, including Scientific American. If you have any comments or questions about the article, you can contact him at dtso.info@displaymate.com.

 

DisplayMate Display Optimization Technology

All Tablet and Smartphone displays can be significantly improved using DisplayMate’s advanced scientific analysis and mathematical display modeling and optimization of the display hardware, factory calibration, and driver parameters. We help manufacturers with expert display procurement and quality control so they don’t make mistakes similar to those that are exposed in our Display Technology Shoot-Out series. We can also improve the performance of any specified set of display parameters. This article is a lite version of our intensive scientific analysis – before the benefits of our DisplayMate Display Optimization Technology, which can correct or improve all of these issues. If you are a display or product manufacturer and want to significantly improve display performance for a competitive advantage then Contact DisplayMate Technologies.

 

About DisplayMate Technologies

DisplayMate Technologies specializes in proprietary sophisticated scientific display calibration and mathematical display optimization to deliver unsurpassed objective performance, picture quality and accuracy for all types of displays including video and computer monitors, projectors, HDTVs, mobile displays such as smartphones and tablets, and all display technologies including LCD, OLED, 3D, LED, LCoS, Plasma, DLP and CRT. This article is a lite version of our intensive scientific analysis of Tablet and Smartphone mobile displays – before the benefits of our advanced mathematical DisplayMate Display Optimization Technology, which can correct or improve many of the display deficiencies. We offer DisplayMate display calibration software for consumers and advanced DisplayMate display diagnostic and calibration software for technicians and test labs.

 

For manufacturers we offer Consulting Services that include advanced Lab testing and evaluations, confidential Shoot-Outs with competing products, calibration and optimization for displays, cameras and their User Interface, plus on-site and factory visits. See our world renown Display Technology Shoot-Out public article series for an introduction and preview. DisplayMate’s advanced scientific optimizations can make lower cost panels look as good or better than more expensive higher performance displays. For more information on our technology see the Summary description of our Adaptive Variable Metric Display Optimizer AVDO. If you are a display or product manufacturer and want to turn your display into a spectacular one to surpass your competition then Contact DisplayMate Technologies to learn more.

 

Article Links:  new iPad 3 and iPad 2 Display Technology Shoot-Out

Article Links:  10 Inch Tablet Display Technology Shoot-Out

Article Links:  7 Inch Tablet Display Technology Shoot-Out

 

Article Links:  Tablet Displays Under High Ambient Lighting Shoot-Out

Article Links:  Automatic Brightness Controls and Light Sensors

 

Article Links:  Mobile Display Shoot-Out Article Series Overview and Home Page

Article Links:  Display Technology Shoot-Out Article Series Overview and Home Page

 

 

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