Flagship OLED and LCD TV Display
Technology Shoot-Out
LG OLED 65 inch 4K
Ultra HD DCI Gamut Curved Screen TV
Samsung LCD 65 inch 4K
Ultra HD DCI Gamut Curved Screen TV
Dr. Raymond M. Soneira
President, DisplayMate Technologies
Corporation
Copyright © 1990-2015 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
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LG OLED TV
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Samsung LCD TV
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Screen Shot Photos of
the TVs
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Introduction
An impressive new
generation of TVs with the very latest advanced display technologies launching
in 2015 include the newest state-of-the-art large screen OLED displays and LCDs
with Quantum Dots and Full Array Local Dimming, plus a new wide DCI Color
Gamut, 4K Ultra HD resolution, and curved screens.
To explore these new
OLED and LCD TV technologies in-depth we have lab tested, analyzed, and
compared side-by-side two 2015 flagship top-of-the-line TVs from LG and Samsung
that have competing display technologies. Both are 65 inch 4K Ultra HD DCI
Color Gamut curved screen TVs – an LG OLED TV (model 65EG9600) and a Samsung
LCD TV (model UN65JS9500).
Dual Content Standards
While both these TVs
have the latest next generation display hardware, the available consumer
content produced for 4K Ultra HD with the DCI Color Gamut is still very scarce.
In 2015 over 99 percent of all currently available consumer content is for the
existing Full HD resolution with its own sRGB / Rec.709 Standard and Color
Gamut. So it is essential that these latest TVs can also accurately display the
large base of existing Full HD content with excellent picture quality. This
content not only includes Over The Air (OTA), Cable, and Satellite TV
broadcasting, but also Blu-ray, DVD, digital camera, web content, internet
streaming, and computer content, including photos, videos and movies, which are
all based on the sRGB / Rec.709 Gamut and Standard. It will take years to build
up a content base for 4K Ultra HD with the DCI Color Gamut, which will become
available first through internet streaming. So we have also measured how well
these TVs reproduce the current Full HD content that everyone is watching now.
There are No LED TVs!
There is still a lot of consumer confusion regarding LED TVs versus OLED
TVs… The first thing we need to clear up is the widespread misunderstanding
created by the marketing of “LED TVs” – there aren’t any! The so-called LED TVs
are just LCD TVs that have a backlight that is made of white LED lights. The
LEDs are not the display, just the backlight, nothing more! OLEDs are an
entirely different class of emissive imaging display technology (that doesn’t
use a backlight). Unfortunately, many people think they already have an
LED/OLED TV at home, but they actually have an LCD TV…
Overview of the Existing and Newest TVs and Standards
If you have a reasonably up-to-date TV purchased within the last 5
years, you most likely have a Full HD 1920x1080 pixel resolution flat screen
LCD or Plasma TV with an sRGB / Rec.709 Standard and Color Gamut. Screen size
has also been increasing quickly, with 60 inches and above the new large screen
high-end, and getting larger. Many of the new screens are also slightly curved
– we’ll explain the advantages below.
The newest TVs have an Ultra HD 3840x2160 pixel resolution, also called
4K, which is twice the resolution of Full HD and has 4 times the number of
pixels. The new DCI (Digital Cinema Initiative) Color Gamut is 26 percent
larger than the current sRGB / Rec.709 Color Gamut, with more saturated Red and
Green Primaries. Ultra HD TVs need 90 percent of DCI Gamut. But please
note that a UHD TV cannot increase the picture resolution or the Color Gamut of
any earlier non-UHD picture content (regardless of what any sales person tells
you). We will examine these issues in detail below.
Latest OLED TV Technology
OLEDs are thin solid
state devices that directly emit colored light. OLED
displays have been improving rapidly with increasing screen size, peak
brightness, and power efficiency. They don’t need a backlight and
supporting optical components so they are considerably thinner and lighter than
LCD displays. As a result, OLED TVs are considerably thinner (with the screen
just 0.2 inches deep for this 65 inch model) and considerably lighter than LCD
TVs – the tested LCD TV is 52 percent heavier than
the OLED TV (without their metal stands). It is also easier to make
OLEDs with curved screens, which we will explain below.
OLED
displays first appeared in consumer products in 2010 on smartphones with 4 inch
screens. Making a large TV size OLED display is considerably more challenging,
so that took a few years more. LG introduced their first generation 55 inch
Full HD OLED TV in 2013, which was the best TV display we had ever tested up to
then – and almost all reviewers agreed that OLED outperformed the best Plasma
and LCD TVs in producing the very highest picture quality. The LG OLED TV that
we test here is not only larger but also has even better display performance
and picture quality.
LG has implemented some
special OLED technology for their TVs. First of all, rather than laying out
three separate sets of OLED Red, Green, and Blue sub-pixels throughout the
screen, the LG TV instead has a single uniform set of OLED White sub-pixels
throughout made as a combined stack of Red, Green, and Blue OLED colors for
each sub-pixel. The sub-pixels then each have their own individual Red, Green
and Blue color filters that select the specific Red, Green or Blue OLED color
for that sub-pixel. This approach greatly simplifies the OLED production,
improves yields, and lowers the manufacturing costs. In addition, LG has also
added a 4th clear sub-pixel to every pixel that just produces pure White. This
increases the display’s power efficiency and also improves color accuracy and
color management.
Latest LCD TV Technology
Samsung also introduced their first generation OLED TV in 2013, but for
the 2015 models they decided to go back to LCDs, most likely due to OLED
manufacturing costs and yields, and to concentrate on the production of smaller
mobile OLED displays.
The Samsung flagship LCD TV that we test here includes the latest
high-end LCD technology, including Full Array Local Dimming to improve the
LCD’s Black Levels, Quantum Dots (which Samsung generically calls
Nano-crystals) to enlarge the Color Gamut and improve display power efficiency,
and a curved screen, which is rather challenging to produce for LCDs.
One rather surprising component for this top-of-the-line TV is that
Samsung is using an LCD panel with PVA LCD technology instead of IPS, FFS, or
PLS LCD technology, which many consumers know are used in the best and highest
performing LCD smartphones, tablets, and monitors because of their excellent
wide viewing angle performance with small color and contrast changes with
viewing angle. Large screen TVs are often watched by multiple viewers from a
wide range of viewing angles, so the wide viewing angles together with the
larger DCI Color Gamut can be expected to produce larger picture quality color
and contrast changes with viewing angle, which we measured and analyze in-depth
below.
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.
4K Ultra HD Resolution
Both of the TVs have Ultra HD 3840x2160 pixel resolution,
also called 4K, which is twice the resolution of Full HD and has 4 times the
number of pixels. The perceived image sharpness that your eyes actually see
depends primarily on your viewing distance to the screen, and also how good
your vision is – the further away you are the lower the image sharpness that
you’ll see. In addition, the viewing conditions like the level of ambient light
and your viewing position and angle can significantly lower image sharpness.
For typical viewing distances Full HD TVs deliver very sharp images – for Ultra
HD the TV display will appear perfectly sharp even if you have much better than
standard 20/20 Vision. This article
covers the sharpness and resolution issue in greater detail.
If the Ultra HD TV receives content with lower resolution
Full HD (1920x1080) or HD (1280x720) or SD (852x480) the TV’s internal
electronic signal processing will automatically upscale and convert the image
content up to 3840x2160 so that it fills the screen. However, something that is
also widely misunderstood, even after upscaling the actual on-screen image
resolution remains the same as the lower resolution original content because
up-scaling cannot provide any additional high resolution image detail
that is not present in the original image. So all Full HD content remains a
Full HD image and is not Ultra HD after upscaling.
Real Viewing Conditions with
Ambient Light and Large Viewing Angles
To see the best picture quality on any display or any TV
requires ideal viewing conditions, which includes watching in absolute darkness
with no ambient light, and watching from a viewing position directly in front
of the center of the screen, called the “Sweet Spot.” TVs are almost never
watched under these ideal viewing conditions. First of all, the screen reflects
any ambient light, which reduces and washes out the picture contrast and
colors, and also reduces the perceived image sharpness.
Second, since only one person at a time can watch from
the central Sweet Spot, how the picture quality changes (degrades) with viewing
position and viewing angle is extremely important. Both of these real world
viewing conditions have a major impact on picture quality – we’ll examine them
both with detailed measurements. We’ll cover the Viewing Angle issues last so
they can each be compared with the ideal 0 degrees Viewing Angle performance we
examine first. Be forewarned that the Samsung LCD TV shows large viewing angle
changes, which we’ll cover in detail below…
Curved Screens
Both TVs have curved screens, which first appeared on
OLED and LCD production TVs in 2013, but the curvature is actually relatively
small, only about 2.1 inches (5.3 cm) in-depth (from the edge to the screen
center) on these 65 inch TVs. This slight curvature has a real purpose – it
significantly reduces the reflections of ambient light from the screen, which
improves image contrast, and it also reduces the (keystone) optical distortion
in the screen image geometry, particularly away from the central Sweet Spot at
larger viewing angles.
Because the screen curvature is small, it is barely
noticeable when watching the screen from normal viewing distances, particularly
in low ambient light, which is ideal for watching TV. Since we are accustomed
to watching perfectly flat screens some people don’t like the change in screen
geometry – fortunately many high-end TVs are available with curved or flat
screens. Whether you prefer a curved or flat screen is primarily subjective, but
a slightly curved screen does provide several important objective optimal
visual advantages, which are explained in detail in this earlier article.
Picture Modes
All high-end TVs include a number of user selectable
Picture Modes, each with different intended viewing conditions and applications
that provide different color, brightness, contrast and calibration settings,
and selectable picture processing options. The LG OLED TV has 8 selectable
modes and the Samsung LCD TV has 4 modes. We will analyze the two most
important ones: the native display mode that delivers the highest brightness,
contrast, and color saturation, called the Vivid mode on the LG OLED TV and the
Dynamic mode on the Samsung LCD TV, and the mode that delivers the most
accurate colors and picture quality that is preferred by videophiles, called
the Cinema mode on the LG OLED TV and the Movie mode on the Samsung LCD TV. We
include measurements and analysis for both modes on each TV. For all of the
tests and measurements we used the manufacturer’s default factory settings for
each of the modes and did not make any additional changes or adjustments.
Picture Brightness
High picture brightness for TVs is considered important
by most consumers because TVs are viewed under a wide range of ambient lighting
conditions, and the high image brightness helps to compensate for the reduction
in picture contrast and color saturation from the ambient light that is reflected
off the screen. Under ideal dark viewing conditions (like in movie theaters)
relatively low picture brightness is all that is needed.
Both TVs deliver bright images for typical TV picture
content, which have Average Picture Levels (APL) of 25 percent or less
(compared to an all white screen), which are listed below. The Cinema and Movie
modes are designed for viewing in lower ambient lighting, so they aren’t as
bright as the Vivid and Dynamic modes. While OLEDs were at one time less bright
and less power efficient than LCDs, their brightness and power efficiency are
now typically higher. The visual brightness (Luminance) is measured in terms of
cd/m2, which is often referred to as nits.
LG OLED TV Brightness Cinema mode 242 nits
Vivid mode 428 nits
Samsung LCD TV Brightness Movie mode 203 nits
Dynamic mode 415 nits
The brightness for both TVs is affected by the Average
Picture Level (average brightness over the screen) of the picture content. For
high APLs, which can occur with some web and computer content that has lots of
white backgrounds for text, the OLED brightness decreases to 157 to 232 nits
for 50 percent APL, and for an all peak white screen, which has 100 percent
APL, it falls to 91 to 141 nits. Most TV picture content has an APL under 25
percent. Since the screens are fairly large, they will produce a lot of light
with high APL images, so the reduced screen brightness at high APLs might
actually be more comfortable visually with large screens.
The brightness (Luminance) for LCD displays generally
doesn’t vary with APL. However, with Local Dimming the maximum brightness
within a zone on the screen is reduced whenever Local Dimming is applied to
that zone. For very low APLs with Local Dimming the peak brightness can
decrease to below 100 nits in order to produce a Black that is 4 times darker
in a zone. We examine LCD Local Dimming in detail below. See the Brightness
and Contrast section for measurements and details. The Brightness also
varies significantly with Viewing Angle, see below.
Display Black Levels and
Contrast Ratios
OLEDs are light emissive displays that produce perfect
image Blacks with 0 cd/m2 Black Levels resulting in an infinite
Contrast Ratio and an infinite Dynamic Range. This is visually striking with
darker picture content, and with letterboxing the outer borders are invisible
for a nice effect.
LCDs are light transmissive displays that cannot fully
block the backlight so they produce very dark grays instead of perfect Blacks.
This results in native Contrast Ratios (peak white to actual black) in the
range of 1,000 to 4,000 for LCDs. For bright picture content the dark gray
blacks normally aren’t noticeable, but with darker picture content the dark
gray background glow can be quite noticeable and it diminishes both the picture
contrast and color saturation.
Different LCD technologies have different Black Levels
and native Contrast Ratios. For the Samsung LCD TV we measured an impressive
native Contrast Ratio of 3,844 the highest ever for an LCD. But that still
results in a Black Level of 0.1 nits, which visually stands out in darker
picture content. These Black Levels can be significantly reduced by selectively
dimming the backlight when there is darker picture content with a technology
called Local Dimming, which we examine in detail below and also in the Viewing
Tests. See the Brightness
and Contrast section for measurements and details. The LCD Black Levels and
Contrast Ratios also vary significantly with Viewing Angle, see below.
Low Screen Reflectance
The screens on all displays are mirrors that reflect
light from everything that is illuminated anywhere in front of the screen
(especially anything behind the viewers), including lamps, ceiling lights,
windows, direct and indirect indoor and outdoor sunlight, which washes out the
on-screen colors, degrades image contrast, and interferes with seeing the
on-screen images. The lower the Screen Reflectance the better. In fact,
decreasing the Screen Reflectance by 50 percent doubles the effective Contrast
Ratio in Ambient Light, so it is very important.
Most TVs, monitors, smartphones and tablets have a Screen
Reflectance of 5 percent or more. The previous Low Reflectance record holders
that we measured were the 2013 LG OLED TV
at 2.2 percent and the Apple
iPad Air 2 Tablet at 2.5 percent. The new LG OLED TV breaks all previous
records, with a very impressive 1.2 percent Reflectance, the lowest we have
ever measured for a display. The Samsung LCD TV also does very well, with an
impressive 2.2 percent Reflectance. However, as a result of its much lower
Reflectance, the LG OLED TV has about double the effective Contrast and
Contrast Rating for High Ambient Light as the Samsung LCD TV. See the Screen
Reflections and Brightness
and Contrast sections for measurements and details.
LCD Local Dimming
The Samsung LCD TV also includes advanced Full
Array Local Dimming, which can visually improve the Black brightness levels of
LCDs. With this technology the TV backlight is divided into approximately 180
independently dimmable zones (18x10) that allow dark areas of an image to have
darker less visually noticeable Black levels, which can be noticeable with
darker image content on LCDs. Also see the Viewing
Tests section below for additional details.
Local Dimming changes both the dark and bright
picture content:
With Local Dimming, complex algorithms are
needed to make a complex set of compromises between image brightness and Black
levels across the screen, and all 180 zones have to be adjusted real-time frame-to-frame
with the changing video content. When a particular zone is darkened it produces
lower Black levels but the zone can no longer produce bright pixel content
anywhere within the zone, so its peak brightness is reduced by the same amount
that the Black level is lowered with dimming. A factor of 2 improvement in the
Black level means that the peak brightness is reduced by the same factor of 2
everywhere in the zone – a tradeoff that diminishes some bright picture content
in return for a darker black. Another crucial issue is that adjacent and nearby
zones must all have similar coordinated dimming levels so that visible
differences between adjacent zones that can give rise to visually noticeable
quilting, halos, and blooming effects, are not visually apparent. This means
that many areas in an image cannot be sufficiently darkened when the picture
content in nearby zones is brighter.
Screen
shots demonstrating Local Dimming:
Below are
photographic screen shots of both TVs to demonstrate these Black level and
Local Dimming issues. Both
photos were taken of images made with just single pixel width horizontal and
vertical lines – the first is along all the outside edges of the screen, and
the second just has a single horizontal line across the center of the screen. The photos were taken in the dark, with no light falling on
the screens, but with the area behind the TVs dimly backlit for visual
reference. A few tiny lights in the lab below the TVs are also seen. The
LG OLED TV remains perfectly black except for the single pixel width lines. The
Samsung LCD TV shows large scale areas of the screen with a visible gray
background glow due to the Local Dimming management issues mentioned above. The photos demonstrate the compromises and limitations of
Full Array Local Dimming.
Comparison of OLED with LCD Full Array Local Dimming
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LG OLED
TV
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Samsung
LCD TV
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LG OLED
TV
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Samsung
LCD TV
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Color Gamuts
Both TVs have a native Color Gamut based on the larger
DCI-P3 Gamut proposed for UHD TVs. Although the UHD Alliance standard has not
been finalized, UHD TVs will need 90 percent or more of the DCI-P3 Gamut. We
measured 93 percent of DCI-P3 for the LG OLED TV and 104 percent of DCI-P3 for
the Samsung LCD TV, which are shown in Figure 1 along with other
TV Picture Modes. So both TVs meet the proposed UHD standard. The Samsung LCD
is able to exceed the DCI-P3 Color Gamut by using Quantum Dots, which are
explained in detail in this earlier article.
Since over 99 percent of all currently available consumer
content is based on Full HD, which uses the sRGB / Rec.709 Color Gamut, both
TVs also need to support this Standard Gamut, which is called the Cinema mode
for the LG OLED TV and the Movie mode for the Samsung LCD TV. It is implemented
using Color Management of the larger native DCI Color Gamut. We measured 106
percent of the sRGB / Rec.709 Standard for both TVs, which are shown in Figure 1 along with other
Picture Modes. They are both a very good match to the sRGB / Rec.709 Standard,
with the 6 percent excess primarily resulting from a slightly over saturated
Blue Primary, which isn’t as important as accurate Red and Green primaries as
explained in this article.
See the Colors
and Intensities section and Figure 1 for measurements
and details. The Color Gamuts also vary significantly with Viewing Angle, see
below.
Another very important
point that is widely misunderstood is that the TV should actually be set to
match the Color Gamut that was used in producing the original picture content
that is being shown, and not a larger Color Gamut because that makes the colors
worse, not better. A UHD TV can not increase the Color Gamut of any
earlier non-UHD picture content. Using the larger UHD DCI Color Gamut for Full
HD content can not show additional colors that are not present in
the original content – so it will just exaggerate and distort the true image
colors.
Absolute Color Accuracy
Color accuracy is particularly important for TVs, and
their accuracy has been steadily improving as the result of many more
manufacturers using fully automated color calibration with instruments at the
factory instead of having assembly workers visually tweaking the colors.
We measured the Absolute Color Accuracy of both TVs for
the sRGB / Rec.709 Color Gamut, which accounts for over 99 percent of all
current consumer content. In the future we’ll measure it for the UHD DCI Color
Gamut once the Standard is finalized and a reasonable amount of consumer
content becomes available.
Both TVs have very good color accuracy – both are tied
with an impressive Average Color Error of 1.8 JNCD, which is typically visually
indistinguishable from perfect (but their Maximum Color Errors are larger) –
the most color accurate TVs that we have ever measured. See this Figure for an explanation
and visual definition of JNCD and the detailed Color Accuracy Plots
showing the measured Color Errors for both TVs. See the Colors
and Intensities section and this Figure for measurements
and details. Note that these measurements are only for 0 degrees Viewing Angle
– the Color Accuracy also varies with Viewing Angle in the same way as the
Color Gamut, see below.
Gray Scales and Image
Contrast
The Intensity Scale (sometimes called the Gray Scale)
generally gets less attention, but it is extremely important because it not
only controls the contrast within all displayed images but it also controls how
the Red, Green and Blue primary colors mix to produce all of the on-screen
colors. So if the Intensity Scale doesn't closely follow the Standard that was
used in producing the content then the colors and intensities will be wrong
everywhere in all images.
The steeper the Intensity Scale the greater the image
contrast and the higher the saturation of displayed color mixtures. The
Intensity Scale is logarithmic and its steepness is called the display’s Gamma.
The Gamma for the LG OLED TV Intensity Scale is 2.16, which is fairly close to
the Standard Gamma of 2.20. The Gamma for the Samsung TV is 2.07, which is
noticeably lower than the Standard (and with a large 21 percent Luminance bump
at 35 percent signal intensity). Figure 3 shows the measured
Intensity Scales for the TVs alongside the industry standard Gamma of 2.2. See
the Colors
and Intensities section and Figure 3 for measurements
and details. The Intensity Scales and Gamma also vary significantly with
Viewing Angle, see below.
Changes with Viewing Position
and Angle
Large screen TVs are often watched by multiple viewers
from a wide range of viewing positions and angles. So far we have examined how
the TV displays perform from the ideal central Sweet Spot with a 0 degrees
Viewing Angle. We now consider how each of the TV display performance and
picture quality metrics examined above change (degrade) with Viewing Angle. All
displays and display technologies show some variation for each metric with
angle. The smaller the change with Viewing Angle the better. We repeated the
tests and measurements at a 45 degree Viewing Angle, which is typical for TVs,
and also at 60 degrees to see what happens at larger angles.
As shown in detail below, the LG OLED TV shows relatively
small changes with Viewing Angle for all of the display metrics, as we had
expected. On the other hand, the Samsung LCD TV shows rather large changes with
Viewing Angle for all of the display metrics, which was unexpected and
surprising for a high-end TV. The source of the problem is that Samsung is using an LCD panel with PVA LCD technology
instead of IPS, FFS, or PLS LCD technology, which many consumers know are found
in the best and highest performing LCD smartphones, tablets, and monitors
because of their excellent wide viewing angle performance with small color and
contrast changes with angle. In addition, using a larger DCI Color Gamut
together with a PVA LCD magnifies the color changes and shifts with angle.
Measurements with Viewing Angle
The changes with Viewing Angle are quite large and very
important so we covering them in detail below. We cover each of the display
metrics in turn, and then include some screen shot photos of the TVs to show
these effects visually. The links below are for the Figures that clearly show
how each of the metrics varies with Viewing Angle. All of the display
performance metrics that we measured and discussed above can change
significantly, even drastically with Viewing Angle and position. We examine
each one in turn:
Color
Changes and Shifts with Viewing Angle: One
of the biggest challenges for TV picture quality is minimizing any noticeable
changes or shifts in the image colors with Viewing Angle – both the hue and
saturation. Pure White and the fully saturated native pure Red, Green and Blue
Primary Colors for each display change the least with Viewing Angle – it is
actually the large range of colors that lie in the middle in between the outer
fully saturated native Primaries and the inner central White point that change
the most with Viewing Angle, and that is where most TV picture content exists.
To evaluate the Color Changes with Viewing Angle we
measured the shift in the Primary Colors for the sRGB / Rec.709 Color Gamut,
which accounts for over 99 percent of the current consumer content. This shows
how the internal sRGB / Rec.709 Primary Colors change, but these same effects
apply to most picture colors and content as explained above. For the LG OLED TV
the entire Color Gamut changes only slightly, increasing by 7 and 9 percent at
45 and 60 degrees. For the Samsung LCD TV the entire Color Gamut changes
drastically, decreasing by 42 and 59 percent at 45 and 60 degrees, producing
very noticeable color shifts and loss of color saturation with Viewing Angle.
This Figure shows
how the colors shift from 0 degrees to 45 and 60 degrees. Screen shots are
shown below.
Brightness
Decreases with Viewing Angle: For almost
all displays the picture brightness will decrease with increasing in Viewing
Angle. As long as it isn’t too large it’s not really objectionable because it
doesn’t distort or reduce the picture quality, it just dims the picture. For
the LG OLED TV the maximum brightness (Luminance) decreases by just 19 percent
at 45 degrees, but the Samsung LCD TV has a large 52 percent decrease, which is
quite noticeable and significant. This Figure shows
how the Brightness decreases in 5 degree increments up to 60 degrees.
Black
Level Increases with Viewing Angle: There is
no change in the Black Level with Viewing Angle for the LG OLED TV (0 percent
increase), but there is a very large increase in the Brightness of the Black
Level for the Samsung LCD TV, an increase of 419 percent at 45 degrees, often
resulting in a noticeable background haze across the image even at moderate
Viewing Angles. This increase does not depend or change with LCD Local Dimming.
This Figure shows
how the Black Level increases in 5 degree increments up to 60 degrees.
Intensity
Scale Changes with Viewing Angle: There is
essentially no change in the Intensity Scale for the LG OLED TV with Viewing
Angle but a very large change for the Samsung LCD TV, which is shown in this Figure.
The Intensity Scale variation with angle is the root cause of all the other
changes with angle.
Screen Shot Photos with Viewing Angle
The photos below are screen
shots of both TVs at 0 degrees and 45 degrees Viewing Angles for visually
comparing the changes with Viewing Angle. For the 45 degrees side viewing
angle, the keystone geometric distortion that is normally seen from that
position has been removed to make the comparison with 0 degrees more straight
forward. Note that the best way to visually evaluate changes with Viewing Angle
is to look at a fixed image while you shift your viewing position. The photos
below are of a Red Barn Door from the DisplayMate Multimedia with
Test Photos Edition.
The LG OLED TV shows only a
slight color change between the 0 and 45 degrees Viewing Angle positions. On
the other hand, the Samsung LCD TV shows relatively large changes in hue,
saturation, and image contrast between the 0 and 45 degrees Viewing Angle
positions for the reasons explained above. The camera exposures were adjusted
to equalize the photo brightness levels, so the differences in display
brightness are not shown. Note that all of the white knobs have roughly the
same appearance and brightness. The Samsung LCD TV shows a more saturated
orange color at 0 degrees as the result of the somewhat different color
calibrations and Intensity Scales for the two TVs (see Figure 2 and Figure 3). The point being
demonstrated here is the color change with Viewing Angle and not the difference
in the color calibration between the two TVs.
LG OLED TV
0 degrees Viewing Angle – Exact Center View
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Samsung LCD TV
0 degrees Viewing Angle – Exact Center View
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LG OLED TV
45 degrees Viewing Angle – View from the Side
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Samsung LCD TV
45 degrees Viewing Angle – View from the Side
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Response Time and Motion Blur
Motion Blur is a well known issue with LCDs that is seen
with rapidly moving objects in the picture, and also when the camera itself
moves, which shifts the entire screen image all at once. It arises because the
Liquid Crystal, which is the active element within an LCD, is unable to change
its orientation and light transmission rapidly enough when the picture changes
from one frame or refresh cycle to the next. OLEDs, as solid state emissive
devices, have very fast Response Times: LG specifies the OLED Response Time at
0.1ms, which is more than a factor of 10 faster than LCDs.
For
the Response Time and Motion Blur tests we photographed a DisplayMate Multimedia with
Motion Edition Test Pattern moving at a moderately fast Full HD 1,272
pixels per second using a Nikon DSLR camera with a shutter speed of 1/320th of a second, which is
faster than the Refresh Rate and motion compensation rate for the TVs. At 1,272
pixels per second it takes 1.2 seconds to move diagonally across the entire
screen.
The LG OLED TV screen shot below shows a single crisp
image, without any visible latent blur or ghost images left over from earlier
refresh cycles or any shading in the image (see below). This indicates a
Response Time that is significantly faster than 5ms.
For the Samsung LCD TV screen shot it is possible to make
out a total of 4 images of the moving diamond-box (the current and 3 earlier
images) on the gray background at the 120 Hz refresh rate, indicating a
Response Time in the neighborhood of 20 ms for this LCD.
The darker gray shading gradient to the bottom and right
sides of the Samsung LCD TV screen shot photograph is due to the limited
response time of the LCD to the gray block moving on the black screen
background. Gray response times are typically longer.
Response Time and Motion Blur Screen Shots
Full HD 1,272 Pixels
Per Second Motion with a 1/320th second screen photo
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LG OLED TV
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Samsung LCD TV
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|
TV Display Power Efficiency
Display power efficiency is extremely important for
mobile displays, but it is also very important for TVs for several reasons: one
is that there are roughly 330 million TVs in the US that are on over 600
billion hours per year, accounting for almost 10 percent of the total US
residential power consumption.
Display power efficiency is also very important because
the power gets transformed into heat, which affects the performance of the
display. For example, in the lab tests it took the Samsung LCD almost 2 hours
to reach a stable operating point (and internal temperature), something that
consumers are not likely to notice, but which clearly affects the display’s performance
(and delayed the measurements while we waited for it to stabilize).
Display power efficiency is especially important for
OLEDs because the power has to be distributed directly to every individual
sub-pixel on the screen via the backplane (while for LCDs the backlight power
is completely separate from the display panel). So for OLEDs, improving their
light emission power efficiency is the primary method needed to increase the
peak image brightness, which is critical.
For both TVs the display power used depends on the
picture content. OLEDs are light emissive so the brighter the content the more
power they use (and none for black). For standard LCDs the display power is
independent of content (same for all white or all black). However, the Samsung
LCD TV has Local Dimming so it uses less power on darker content because of the
local dimming of the backlight.
We measured the average display power for various
programs of bright and dark picture content. The LG OLED TV used an average of
39 percent less power than the Samsung LCD TV for the Cinema/Movie modes, and
an average of 17 percent less power for the Vivid/Dynamic modes for identical
Brightness (Luminance) levels. This is an impressive achievement for OLEDS. See
the Display
Power section for measurements and details.
Viewing Tests
In addition to the comprehensive set of lab tests and
measurements we also watched lots of TV and movie content, with both TVs side-by-side
showing identical content all viewed simultaneously for direct comparisons.
Samsung LCD TV
When viewed exactly from the central Sweet Spot with a 0
degrees Viewing Angle, the Samsung LCD TV looked very good, with excellent
color accuracy but with slightly reduced image contrast due to a slightly too
shallow Intensity Scale. The Full Array Local Dimming worked well and
significantly improved the Black Levels. Local Dimming worked best in solid
black areas, like in letterboxing, where the outside borders nicely
disappeared. But with mixed dark and light picture content Local Dimming isn’t
able to sufficiently reduce the Black Levels in the dark portions of the image
sufficiently, so they appeared as muffled dark gray areas. This was
particularly noticeable with the LG OLED TV right next to it with perfect
blacks that showed what the dark picture should actually look like.
However, even a small change in viewing position resulted
in large noticeable changes and degradation in the picture quality. The Black
Levels increased tremendously with Viewing Angle (by a factor of 5.2 at 45
degrees in the measurements) resulting in a quite noticeable background haze
across the image, which not only washed out the contrast but also washed out
the colors in all but the very brightest and most vibrant pictures. This is the
result of using a PVA LCD panel instead of IPS, FFS, or PLS LCD panels that
have significantly better viewing angle performance.
LG OLED TV
The viewing tests for the LG OLED TV were simply exceptional,
with the picture quality visually indistinguishable from perfect, with
excellent color accuracy and image contrast accuracy (from a near perfect
Intensity Scale) together with perfect Black Levels. The very challenging set
of DisplayMate Test and Calibration Photos that we use to evaluate picture
quality looked absolutely stunning and Beautiful,
even to my experienced hyper-critical eyes.
Even with large changes in viewing position and viewing
angle, the picture quality remained excellent with no visible changes in the
near perfect image contrast and no changes in the perfect Blacks Levels, and
just slight changes in brightness and relatively small changes in color with
angle. So everyone watching the TV sees an excellent picture regardless of their
viewing location.
OLED and LCD TV Conclusions:
Testing both of these flagship high-end top-of-the-line
OLED and LCD TVs side-by-side at the same time using simultaneous identical
test patterns and picture content was incredibly interesting, and also incredibly
revealing because they were side-by-side for all of the tests and comparisons.
Some of the test results and conclusions summarized below
are not that unexpected. OLED TVs have all of the same high performance picture
quality advantages as Plasma TVs, which were overwhelmingly preferred by
videophiles over traditional LCDs – and OLEDs now significantly outperform the
Plasmas across the board in all categories – so the performance advantages are
even greater for OLEDs. However, the latest high-end LCDs also outperform
traditional LCDs…
Below we list separately the OLED TV and LCD TV
Conclusions together with their respective strengths, weaknesses, and future
improvements. See the main Display
Shoot-Out Comparison Table for all of the DisplayMate Lab measurements and
test details, and see the Results Highlights section
above for detailed explanations of the Conclusions presented below.
OLED TV Conclusions
The LG Flagship OLED TV performed extremely well
throughout all of the lab tests and viewing tests. It is unquestionably the
best performing TV that we have ever tested or watched… with absolutely
stunning and beautiful picture quality across the board. In terms of picture
quality the LG OLED TV is visually indistinguishable from perfect. Even in
terms of the exacting and precise lab measurements it is close to ideal.
The LG OLED TV is far better than the best Plasma TVs in
every display performance category, and even better than the $50,000 Sony
Professional CRT Studio Monitors that up until recently were the golden
standard for picture quality.
The LG OLED
TV outperformed the Samsung LCD TV in every category except Brightness
(Luminance) for image content with Average Picture Levels (APL) greater than 25
percent. The under 25 percent APL range covers all standard TV content,
including digital photos, videos and movies, but does not include Smart TV or
PC applications, which can have higher APLs from text screens on white
backgrounds.
The LG OLED TV performed the
best in these categories:
Much lower Screen Reflectance – higher Brightness for
both tested picture modes – perfect Black Levels – infinite Contrast Ratio –
higher Contrast Rating for High Ambient Light – higher Absolute Color Accuracy
(a tie only at 0 degrees) – more accurate Intensity Scale and Gamma – much
better Viewing Angle performance for all tested metrics – very fast Response
Time and no Motion Blur – higher display Power Efficiency for TV video content.
See the Results Highlights section and Display
Shoot-Out Comparison Table for all of the measurements and details.
Improving OLEDs:
It is especially interesting that LG has continued to
systematically improve the display performance of their already high
performance OLED TVs. In almost every single test and measurement category the
tested 2015 OLED TV performs better than the first generation model that we
tested in 2013, which already had excellent display performance and we rated it
the best TV tested up to that time. Those continuing improvements are what lead
to top display performance, which we hope LG will continue for their next
generation OLED TVs.
What should come in the next
generation of OLED TVs?
The OLED performance for all of the above display metrics
can undoubtedly continue to be improved. In particular, it is a safe bet that
the Brightness and Power Efficiency will definitely increase again, and we’ll
also see improvements in the Color Gamut, Color Accuracy, and Viewing Angle
performance.
From a consumer perspective:
The most important consumer issue for LG will be bringing
down the price of their OLED TVs as quickly as possible. The retail price for
this state-of-the-art Flagship OLED TV is $6,000 US (September 2015), way above
what most consumers can afford. But putting this into perspective, early
high-end Plasma TVs cost considerably more than $10,000 (and that’s not
counting inflation), so OLED prices will undoubtedly come down soon – in fact,
earlier generation 55 inch LG OLED Full HD TVs are now available for $2,000.
Finally, because OLEDs are solid state devices, it is quite possible that their
production cost will some day be lower than LCDs.
LCD TV Conclusions
The Samsung LCD TV performed exceptionally well for an
LCD display with its state-of-the-art Full Array Local Dimming, Quantum Dots,
and a curved screen, but that applies only
when it is being viewed straight ahead from directly in front of the center of
the screen, which is called the Sweet Spot. From other viewing positions and
viewing angles the display performance and picture quality decrease noticeably.
The Samsung LCD TV performed the
best in only one category:
Higher Brightness for Average Picture Levels greater than
25 percent. This higher APL range covers Smart TV and PC applications, which
often have higher APLs due to the use of white backgrounds for text. In two
other test categories it came close to the LG OLED TV in Brightness for APLs
under 25 percent, and in Absolute Color Accuracy, but only for 0 degrees
Viewing Angle. See the Results Highlights section and
Display
Shoot-Out Comparison Table for all of the measurements and details.
LCD’s inherent strengths:
LCDs like all display technologies have their own
particular inherent strengths and weaknesses. LCD’s strengths include being
able to produce very high image brightness by using powerful backlights, very
wide Color Gamuts by using Quantum Dots, very large size screens, and at much
lower cost compared to other competing technologies. As a result, LCDs now have
over 90 percent market share, so the majority of consumers are satisfied with
LCD performance and picture quality.
LCD’s competition and responses:
While LCDs have by far the highest current market share,
competing technologies from CRT, to Plasma, and now OLED have in turn played to
some of the LCD’s weaknesses by producing very high performance displays with very
low Black levels, very high Contrast Ratios, very wide viewing angles without
color, contrast, or black shifts, and very fast response times without Motion
Blur. In turn, high-end LCDs like those on the Samsung TV have responded by
adding Full Array Local Dimming to improve the Black levels, Quantum Dots to
increase the Color Gamut, and advanced signal processing to improve the
Response Time and reduce Motion Blur. While high-end LCD performance has been
significantly improved in these areas, OLEDs still deliver higher performance
as our extensive
tests have shown.
Large changes with viewing
position and angle:
The Samsung LCD TV shows rather large changes in picture
quality with Viewing Angle for all of the performance metrics – Color,
Brightness, Black Level, and Image Contrast listed
here – which is surprising for a high-end large screen TV because they are
frequently watched by multiple viewers from a wide range of viewing angles. The
source of the problem is that Samsung is using an LCD panel with PVA LCD
technology instead of IPS, FFS, or PLS LCD technology, which many consumers
know are found in the best and highest performing LCD smartphones, tablets, and
monitors because of their excellent wide viewing angle performance with small
color and contrast shifts with angle.
Combining PVA with Quantum Dots:
A major strategic technical flaw in the Samsung TV was
combining PVA LCD technology together with a native wide DCI Color Gamut, when
over 99 percent of all current consumer TV, video, digital photo, computer, and
web image content uses the smaller Full HD sRGB / Rec.709 Standard Color Gamut.
The fundamental problem is that PVA LCDs have much larger performance
variations with viewing angle than IPS, FFS, PLS LCDs, and as a result the
color variations with viewing angle are considerably magnified when
implementing the smaller Full HD Color Gamut from the larger native DCI Gamut
as shown in this figure
and explained in detail here.
What should come in the next
generation of LCD TVs?
LCDs are a great display technology with lots of inherent
native strengths that manufacturers should concentrate on and exploit instead
of trying to pursue OLEDs on their native strengths. So LCD manufacturers
should exploit very high image brightness, very large screens, very wide color
Gamuts with Quantum Dots to improve picture quality in high ambient light. For
wide Color Gamut displays and TVs using Quantum Dots it is essential they use
IPS, FFS, PLS or equivalent LCD technologies with excellent Viewing Angle
performance to eliminate the large color shifts with angle that are produced by
PVA (and other) LCD technologies. Finally, stick with flat screens – curved
screens are especially challenging to implement for LCDs – leave those to
OLEDs.
Display Shoot-Out Comparison Table
Below we
examine in-depth the LG OLED TV (Model 65EG9600) and the Samsung LCD TV (Model UN65JS9500)
based on
objective Lab measurement data and criteria.
For
additional background information see our 2013 LG OLED TV
Display Technology Shoot-Out.
For
comparisons with the other TVs and Multimedia displays see our Display Technology Shoot-Out
series.
Many of the
measurements were made with a Konica
Minolta CS-2000 Spectroradiometer.
The
measurements are listed under these section headings: Screen
Reflections, Brightness
and Contrast,
Colors
and Intensities, Viewing
Angles, OLED and
LCD Spectra, Display
Power.
TV Specifications
Categories
|
LG OLED
TV
Model
65EG9600
|
Samsung
LCD TV
Model
UN65JS9500
|
Comments
|
Display Technology
|
OLED TV Display Panel
White Sub-Pixels
in addition to
Red-Green-Blue
Sub-Pixels
|
LCD TV
Display Panel
PVA LCD
Technology
Full Array
Local Dimming
Quantum
Dots / Nano-crystals
|
Organic Light Emitting Diode
Patterned Vertical Alignment
Liquid Crystal Display
|
Display Size
|
64.5
inches
Curved
Screen
|
64.5
inches
Curved
Screen
|
Size is the Diagonal screen length.
|
Screen Shape
|
16:9 =
1.78
Aspect
Ratio
|
16:9 =
1.78
Aspect
Ratio
|
The 16:9 Aspect Ratio
is a perfect match for Widescreen TV
video.
|
Screen Area
|
1778
Square Inches
|
1778
Square Inches
|
A better measure of size than the
diagonal length.
|
Display Resolution
|
3840 x
2160 pixels
4K Ultra
HD
|
3840 x
2160 pixels
4K Ultra
HD
|
Both TVs have double the Full HD
Resolution.
|
Total Number of Pixels
|
3.7
Mega Pixels
|
3.7
Mega Pixels
|
Total Number of Pixels.
|
Pixels Per Inch
|
50
Pixels Per Inch
|
50
Pixels Per Inch
|
Sharpness depends on the viewing distance
and PPI.
See
this on sharpness and visual acuity for displays.
|
20/20 Vision Distance
where Pixels or Sub-Pixels
are Not Resolved
|
50
inches
4.2 feet
1.3
meters
|
50
inches
4.2 feet
1.3
meters
|
For 20/20 Vision the minimum viewing
distance
where the screen appears perfectly sharp
to the eye.
|
Appears Perfectly Sharp
at Typical Viewing Distances
|
Yes
|
Yes
|
Typical Viewing Distances for a large TV
of this size
are 8 feet (2.4 meters) or more.
|
Screen Reflections
All display screens are mirrors – but that is
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. Our Lab
Measurements include Average Reflectance for Ambient Light from
all Directions and for Mirror Reflections.
|
Categories
|
LG OLED
TV
|
Samsung
LCD TV
|
Comments
|
Average Screen Reflection
Light From All Directions
|
1.2
percent
for
Ambient Light Reflections
Excellent
|
2.2 percent
for
Ambient Light Reflections
Excellent
|
Measured using an Integrating Hemisphere
and
a Spectroradiometer.
|
Relative Brightness of the
Reflected Ambient Light
|
100 percent
Best
|
183 percent
Much Higher
|
Relative Brightness of the Reflected
Ambient Light expressed as a percentage of the lowest amount.
|
Mirror Reflections
Percentage of Light Reflected
|
2.1 percent
for Mirror Reflections
Very Good
|
3.1 percent
for Mirror Reflections
Very Good
|
These are the most annoying types of
Reflections.
Measured using a Spectroradiometer and a
narrow
collimated pencil beam of light
reflected off the screen.
|
Relative Brightness of the
Mirror Reflections
|
100 percent
Best
|
148 percent
Much Higher
|
Relative Brightness of the Mirror Light
Reflections expressed as a percentage of the lowest amount.
|
Brightness and Contrast
The TV Brightness and Contrast varies with the
Picture Mode and the Average Picture Level APL of the Picture Content.
All Measurements are for 0 degrees
Viewing Angle.
|
Categories
|
LG OLED
TV
|
Samsung
LCD TV
|
Comments
|
Very Low Level Picture Content
Measured Brightness
1% Average Picture Level
|
Cinema
mode 242 cd/m2
Vivid
mode 433 cd/m2
|
Movie mode 198 cd/m2
Dynamic mode 226 cd/m2
Local
Dimming
|
This is the Peak Brightness for a screen
that
has only a tiny 1% Average Picture
Level.
|
Typical TV Picture Content
Measured Brightness
25% Average Picture Level
|
Cinema
mode 242 cd/m2
Vivid
mode 433 cd/m2
|
Movie mode 203 cd/m2
Dynamic mode 415 cd/m2
|
This is the Peak Brightness for typical
TV content
that has a 25% Average Picture Level.
|
Smart TV and PC Content
Measured Brightness
50% Average Picture Level
|
Cinema
mode 157 cd/m2
Vivid
mode 232 cd/m2
|
Movie mode 206 cd/m2
Dynamic mode 416 cd/m2
|
This is the Peak Brightness for typical
Smart TV
and PC content that has a 50% Average
Picture Level.
|
All White Screen
Measured Brightness
100% APL Full Screen White
|
Cinema
mode 91 cd/m2
Vivid
mode 141 cd/m2
High APL
|
Movie mode 207 cd/m2
Dynamic mode 419 cd/m2
|
This is the Brightness for an entirely
all white screen
with 100% Average Picture Level.
|
Low Ambient Light
|
Black Brightness at 0 lux
|
Cinema
mode 0 cd/m2
Vivid
mode 0 cd/m2
|
Without Local Dimming
Movie mode 0.066 cd/m2
Dynamic mode 0.109 cd/m2
With Local
Dimming for All Black
0 cd/m2
|
The Black Luminance is true zero for the
OLED.
The Black Luminance is zero for the LCD
only
when the array zone and all of its
neighboring
zones are turned off.
|
True Contrast Ratio at 0 lux
Relevant for Low Ambient Light
|
Infinite
|
Movie mode 3,136 cd/m2
Dynamic mode 3,844 cd/m2
|
This is the native true Contrast Ratio
for each display.
Local Dimming of the backlight does not
change the
LCD Contrast Ratio between maximum and
minimum.
|
High Ambient Light
|
Typical TV Picture Content
Contrast Rating
for High Ambient Light
25% Average Picture Level
|
Cinema
mode 202
Vivid mode 357
|
Movie
mode 92
Dynamic
mode 189
|
Indicates how easy it is to see the
screen
under high ambient lighting.
Defined as Maximum Brightness / Average Reflectance.
See High
Ambient Light Screen Shots
|
Relative Contrast Rating
for High Ambient Light
25% Average Picture Level
|
Cinema
mode 100 percent
Best
|
Movie
mode 46 percent
Much Lower
|
Relative Contrast Rating for High
Ambient Light
expressed as a percentage of the highest
value.
For Typical TV Picture Content including
video, movie, and photographic content.
|
Vivid
mode 100 percent
Best
|
Dynamic
mode 53 percent
Much Lower
|
Colors and Intensities
The Color Gamut, Intensity Scale, and White Point
determine the quality and accuracy of all displayed images and all
the image colors. A bigger Color Gamut is
definitely Not Better because the display needs to match all the standards
that were used when the content was produced.
All Measurements are for 0 degrees
Viewing Angle.
|
Categories
|
LG OLED
TV
|
Samsung
LCD TV
|
Comments
|
Color of White
Color Temperature in degrees
Measured in the dark at 0 lux
See Figure 1
|
Cinema Mode
6,724 K
0.6 JNCD
from D65 White
Vivid Mode
11,694 K
9.3 JNCD
from D65 White
Intentionally
Bluish
See Figure 1
|
Movie Mode
6,512 K
0.1 JNCD
from D65 White
Dynamic
Mode
14,473 K
11.1 JNCD
from D65 White
Intentionally
Bluish
See Figure 1
|
D65 with 6,500 K is the standard color
of White
for most Consumer Content and needed for
accurate color reproduction of all
images.
JNCD is a Just Noticeable Color Difference.
See Figure 1
for the plotted White Points.
See Figure 2 for the
definition of JNCD.
|
Color Gamut
Measured in the dark at 0 lux
See Figure 1
|
Cinema Mode
106
percent
sRGB /
Rec.709
Vivid Mode
93 percent
DCI-P3
See Figure 1
|
Movie Mode
106
percent
sRGB /
Rec.709
Dynamic
Mode
104
percent DCI-P3
See Figure 1
|
sRGB / Rec.709 is the color standard for
over
99 percent of current consumer content
and
is needed for accurate color
reproduction.
The new DCI Color Gamut is 26 percent
larger
than the sRGB / Rec.709 Color Gamut.
|
Color Accuracy
|
Absolute Color Accuracy
Average Color Error at 0 lux
0 degrees Viewing Angle
For 21 Reference Colors
Just Noticeable Color Difference
See Figure 2
|
Cinema
Mode
Average Color Shift
From sRGB
/ Rec.709
Δ(u’v’)
= 0.0070
1.8 JNCD
Excellent
See Figure 2
|
Movie Mode
Average Color Shift
From sRGB
/ Rec.709
Δ(u’v’)
= 0.0072
1.8 JNCD
Excellent
See Figure 2
|
JNCD is a Just Noticeable Color Difference.
See Figure 2 for the
definition of JNCD and for
Accuracy Plots showing
the measured Color Errors.
Average Errors below 3.5 JNCD are Very
Good.
Average Errors 3.5 to 7.0 JNCD are
Good.
Average Errors above 7.0 JNCD are
Poor.
|
Absolute Color Accuracy
Largest Color Error at 0 lux
0 degrees Viewing Angle
For 21 Reference Colors
Just Noticeable Color Difference
See Figure 2
|
Cinema Mode
Largest Color Shift
From sRGB
/ Rec.709
Δ(u’v’)
= 0.0146
3.7 JNCD
for Blue
Very Good
See Figure 2
|
Movie Mode
Largest Color Error
From sRGB
/ Rec.709
Δ(u’v’)
= 0.0160
4.0 JNCD
for Blue
Very Good
See Figure 2
|
JNCD is a Just Noticeable Color Difference.
See Figure 2 for the
definition of JNCD and for
Accuracy Plots showing
the measured Color Errors.
Largest Errors below 7.0 JNCD are
Very Good.
Largest Errors 7.0 to 14.0 JNCD are
Good.
Largest Errors above 14.0 JNCD are
Poor.
This is twice the limit for the Average
Error.
|
Intensity Scale
|
Intensity Scale and
Image Contrast
See Figure 3
|
Smooth and
Straight
Very Good
See Figure 3
|
Somewhat
Irregular
Reduced
Contrast
Good
See Figure 3
|
The Intensity Scale controls image
contrast needed
for accurate Image Contrast and Color reproduction.
See Figure 3
|
Gamma for the Intensity Scale
Larger has more Image Contrast
See Figure 3
|
2.16
Very Good
Gamma
Slightly Too Low
|
2.07
Good
Gamma Too
Low
|
Gamma is the log slope of the Intensity
Scale.
Gamma of 2.20 is the standard and needed
for
accurate Image Contrast and Color
reproduction.
See Figure 3
|
Image Contrast Accuracy
|
Very Good
|
Good
|
See Figure 3
|
Viewing Angles
The variation of
Brightness, Contrast, and Color with Viewing Angle is especially important
because Large screen TVs are often watched by multiple viewers from a wide
range of viewing positions and angles.
Color Changes and
Shifts with Viewing Angle
One of the biggest challenges for TV picture quality is
minimizing any noticeable changes or shifts in the image colors with Viewing
Angle – both the hue and saturation. Pure White and the fully saturated
native pure Red, Green and Blue Primary Colors for each display change the
least with Viewing Angle – it is actually the large range of colors that lie
in the middle in between the outer fully saturated native Primaries and the
inner central White point that change the most with Viewing Angle, and that
is where most TV picture content exists.
To evaluate the Color Changes with Viewing Angle we
measured the shift in the Primary Colors for the sRGB / Rec.709 Color Gamut,
which accounts for over 99 percent of the current consumer content. This
shows how the internal sRGB / Rec.709 Primary Colors change, but the same
effects apply to most other picture colors as explained above. For the LG
OLED TV the entire Color Gamut changed slightly, increasing by 7 and 9
percent at 45 and 60 degrees. For the Samsung LCD TV the entire Color Gamut
changed drastically, decreasing by 42 and 59 percent at 45 and 60 degrees,
producing very noticeable color shifts and loss of color saturation with
Viewing Angle. This Figure
shows how the colors shift from 0 degrees to 45 and 60 degrees.
Brightness
Decreases with Viewing Angle
For almost all displays the picture brightness will
decrease with increasing in Viewing Angle. As long as it isn’t too large it’s
not really objectionable because it doesn’t distort or reduce the picture
quality, it just dims the picture. For the LG OLED TV the maximum brightness
(Luminance) decreases by just 19 percent at 45 degrees, but the Samsung LCD
TV has a large 52 percent decrease, which is quite noticeable and
significant. This Figure shows
how the Brightness decreases in 5 degree increments up to 60 degrees.
Black Level Increases
with Viewing Angle
There is no change in the Black Level with Viewing
Angle for the LG OLED TV (0 percent increase), but there is a very large
increase in the Brightness of the Black Level for the Samsung LCD TV, an
increase of 419 percent at 45 degrees, often resulting in a noticeable
background haze across the image even at moderate Viewing Angles. This
increase does not depend or change with LCD Local Dimming. This Figure shows how
the Black Level increases in 5 degree increments up to 60 degrees.
Intensity
Scale Changes with Viewing Angle
There is essentially no change in the Intensity Scale
for the LG OLED TV with Viewing Angle but a very large change for the Samsung
LCD TV, which is shown in this Figure.
The Intensity Scale variation with angle is the root cause of all the other
changes with angle.
Screen Shot Photos with Viewing Angle
Screen shot photos of both TVs at 0 degrees
and 45 degrees Viewing Angles for visually comparing the changes with Viewing
Angle are shown here in the Highlights
section.
|
Display Power Consumption
The Display Power varies with the
brightness of the picture content being displayed.
The power was measured with a True PF
RMS Watt Meter.
Below we compare the
Display Power of the LG OLED TV and the Samsung LCD TV for varying picture
content.
The
Average Power was determined from the total watt-hours in a one hour elapsed
time power measurement.
Note that only the Display
Power is shown, which is calculated from the Total TV power by subtracting
the
fixed non-display related
power measured for an all Black screen, which is about 75 watts for each of
the TVs.
|
Content
The Display Power varies
with the brightness of the
picture content
|
LG OLED
TV
Average
Display Power
Display
Luminance
Cinema
Mode with 242 cd/m2
Vivid
Mode with 428 cd/m2
|
Samsung
LCD TV
Average
Display Power
Display Luminance
Movie Mode with 203 cd/m2
Dynamic
Mode with 415 cd/m2
|
Comments
Only
the Display Power is listed.
Total
TV Power is about 75 watts greater.
Display
Luminance
The
Display Power increases with the
Luminance
of the display,
|
Movie with Dark Content
Blade Runner
|
Cinema
Mode 27 watts
Vivid
Mode 96 watts
|
Movie Mode 40 watts
Dynamic
Mode 98 watts
|
Blade Runner has primarily dark picture
content
and therefore requires less power.
|
Movie with Bright Content
Seabiscuit
|
Cinema
Mode 40 watts
Vivid
Mode 107 watts
|
Movie Mode 62 watts
Dynamic
Mode 133 watts
|
Sea Biscuit has primarily bright picture
content
and therefore requires less power.
|
TV Show with Varied Content
NBC Today Show
|
Cinema
Mode 115 watts
Vivid
Mode 201 watts
|
Movie
Mode 134 watts
Dynamic Mode 258 watts
|
This TV
news and variety show has a wide range of typical TV picture content.
|
About the Author
Dr. Raymond Soneira is
President of DisplayMate Technologies Corporation of Amherst, New Hampshire,
which produces display 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
displays can be significantly improved using DisplayMate’s proprietary very
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, prototype development, testing
displays to meet contract specifications, and production quality control so
that they don’t make mistakes similar to those that are exposed in our public
Display Technology Shoot-Out series for consumers. This article is a lite
version of our advanced 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 advanced
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, TVs, mobile
displays such as smartphones, smart watches, 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 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. We help manufacturers with expert display procurement,
prototype development, and production quality control so they don’t make
mistakes similar to those that are exposed in our Display Technology Shoot-Out
series. 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. 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.
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