Apple Watch Sapphire vs Glass
Display Shoot-Out
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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The Apple Watches in Ambient Light
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Introduction
The world’s best [and most expensive] watches all have a
sapphire crystal because sapphire is incredibly hard, making them extremely
scratch resistant and almost scratch proof under normal use. But sapphire is
fairly expensive, so most watches instead have a glass crystal, which isn’t as
hard or scratch resistant as sapphire, but still holds up pretty well.
But is there a visual difference between a watch that
uses sapphire versus glass? If you were to hold up two identical watches
side-by-side, the one with a glass crystal would be about 20 percent brighter
than the one with sapphire (due to fundamental principles of optics that reduce
its light transmission), so it appears somewhat darker and duller, particularly
because the light has to pass through the crystal twice. There are some new
upcoming advanced technologies that can make significant improvements on this
issue that we’ll mention below.
The above discussion is for traditional watches, which
work by reflecting ambient light off the watch face that lies below the
crystal. On the other hand, the visual consequences from using sapphire and
glass are considerably greater when they are used on displays, including
smartphones and smart watches, because minimizing screen reflections is
especially important for displays, and sapphire has almost double (191%) the
Reflectance of glass, which we consider next…
Sapphire and Glass for
Displays
Virtually all displays work by emitting image light
rather than by reflecting ambient light like traditional watches. As a result,
any ambient light that is reflected by the cover (glass or sapphire or anything
else) washes out the display’s own image light, degrading picture quality,
reducing its contrast and color saturation, and making it harder to see the
intended image. If you are watching a display in total darkness then the screen
Reflectance doesn’t matter, but it has a surprisingly large effect on every
display, even in subdued indoor ambient lighting, and it makes an enormous
difference outdoors.
We’ll show below how large and how important the
Reflectance effect is by comparing the display on an Apple Watch that has a
Sapphire Crystal to an identical display on an Apple Watch Sport that has Ion-X
Glass. The Apple Watch models are perfect for this comparison because they are
identical except for their sapphire and glass covers. But they look and perform
identically only in the dark…
Lowering Screen Reflectance
The standard way that has generally been used to improve
display performance in ambient light is to fight fire-with-fire and just
continue increasing the display’s Maximum Brightness. But there is a practical
limit to that, plus a brighter display needs more power and a bigger battery.
With some new advanced technologies that will be introduced soon, the
Reflectance of both Sapphire and Glass will be reduced significantly.
We’ll show that the best (and smartest) way to improve
display performance, image contrast, color saturation, screen visibility and
readability in ambient light is to lower the Screen Reflectance. Our test
results and conclusions apply to all displays that are used in ambient
lighting, including smartphones, smart watches, tablets, laptops, PC and video
monitors, even TVs (if you watch during the day or with room lights on at
night), and especially for displays that are mostly used in outdoor
environments like digital signage and automobile displays.
Testing the Apple Watches
In this article we test and compare the display
performance of an Apple Watch with a Sapphire Crystal to an
Apple Watch Sport with Ion-X Glass.
Although their internal OLED displays are identical, they have significant differences in optical performance due to the
sapphire and glass covers. We’ll focus primarily on how differently they
perform in ambient light with both Lab measurements and a side-by-side screen
shot photo for a pure visual demonstration. We’ll cover all of the above issues
and much more, with in-depth comprehensive display tests, measurements and
analysis that you will find nowhere else.
The Display Shoot-Out
For
in-depth testing and analysis of the OLED display on Apple Watch see our
earlier Apple Watch OLED
Display Technology Shoot-Out article. Also see our 2014 Smart Watch Display
Shoot-Out article where we tested and compared the OLED display on the Samsung Gear 2
and the LCD display on the Sony SmartWatch 2.
For this Display Shoot-Out article we are testing and comparing the Apple Watch
with a Sapphire Crystal to an Apple Watch Sport with Ion-X Glass. To examine
the display performance for the Apple Watches we ran our in-depth series of Mobile Display Technology
Shoot-Out Lab tests and measurements in order to determine how the displays
performed. We take display quality very seriously and provide in-depth
objective analysis based on detailed laboratory tests and measurements and
extensive viewing tests with both test patterns, test images and test photos.
All the article results are from our DisplayMate
High Ambient Light Display Test Lab, which can test displays at up to
80,000 lux with our proprietary instrumentation and test patterns.
Results Highlights
In this Results section we provide Highlights of the
comprehensive DisplayMate Lab tests and measurements and extensive visual
comparisons using test photos, test images, and test patterns that are covered
in the advanced sections. The Display
Shoot-Out Comparison Table summarizes the Apple
Watch and Apple Watch Sport Lab
measurements in the following categories: Screen
Reflections, Brightness
and Contrast with Ambient Light, Color Gamut
with Ambient Light, Viewing
Angle Variations. You can also skip these Highlights and go directly to the
Apple Watch Sapphire vs Glass Conclusions.
Overview of the Apple Watch Displays
The Apple Watch comes in 3 models and two sizes – we
tested the larger 42 mm Apple Watch model,
which has a Sapphire crystal, and the 42mm Apple Watch
Sport model, which has Ion-X Glass. Both models have an identical OLED
display. See the Display
Comparison Table for their detailed specs, and our earlier
Apple
Watch OLED Display Technology Shoot-Out article for an in-depth analysis of
the OLED display.
Apple Watch Calibration
One very important and significant result from testing
the two watch displays in the dark at 0 lux is that their photometry and
colorimetry calibration measurements were both very good to excellent, and
almost identical to one another, indicating a careful and accurate systematic
factory calibration – Apple typically has each display individually calibrated.
See the Brightness
and Contrast and Color Gamut
sections and Figure 1 for
measurements and details.
Screen Reflectance
In the dark both Apple Watch displays appear and perform
identically, but in ambient light they appear and perform differently due to
the difference in the Reflectance of Sapphire and Glass.
For the Apple Watch Sport with Ion-X Glass we measured
the Screen Reflectance to be 4.7 percent, while for the Apple Watch with
Sapphire we measured 8.2 percent Screen Reflectance, which is 74 percent higher
than with Glass. Both values are about 0.6 percent higher than just pure
sapphire and glass alone, indicating that Apple has done an excellent job in
optically bonding both the glass and sapphire to the OLED display without an
air gap. See the Reflections
section for measurements and details.
Performance in Ambient Light
The 74 percent higher Reflectance of the Apple Watch with
Sapphire means that its screen will reflect almost twice as much surrounding
ambient light as the Apple Watch Sport with Glass. And it takes surprisingly
little ambient light for that to make a significant visible difference…
Contrast Decrease in Ambient
Light
While the display Contrast Ratios are infinite at 0 lux
absolute darkness, they decrease rapidly with ambient light. At just 500 lux,
which is mid-range indoor ambient lighting, the display Contrast Ratios have
fallen to just 29 with Glass and 17 with Sapphire. That is affected by the
watch’s Light Sensor, which automatically dims the displays according to the
current ambient light level. If we fool the Light Sensor and force the watches
up to their Maximum Brightness of about 480 nits, the Contrast Ratios increase
but are still only 64 with Glass and 38 with Sapphire at 500 lux. That’s
indoors…
At an ambient light level of 2,000 lux, which corresponds
to moderate outdoor lighting in the shade or an overcast sky, the display
Contrast Ratios are just 12 with Glass and 7 with Sapphire. When we fool the
Light Sensor up to Maximum Brightness, the Contrast Ratios increase but are
still only 17 with Glass and 10 with Sapphire at 2,000 lux. However, Full
Daylight that is not in direct sunlight ranges from 10,000 to 25,000 lux – for
10,000 lux the Contrast Ratios are 3 and 2 respectively. See the Brightness
and Contrast with Ambient Light section for measurements and details.
Color Gamut Decrease in
Ambient Light
While their Color Gamuts are both close to 100% of the
sRGB/Rec.709 Standard Gamut at 0 lux absolute darkness as shown in Figure 1, the display Color
Gamuts decrease with ambient light and are 82% with Glass and 69% with Sapphire
at 500 lux, which is mid-range indoor ambient lighting. When we fool the Light
Sensor up to Maximum Brightness the Color Gamuts are 93% and 85% respectively,
as shown in Figure 2.
That’s indoors…
At an ambient light level of 2,000 lux, which corresponds
to moderate outdoor lighting in the shade or an overcast sky, the Color Gamuts
are just 58% with Glass and 39% with Sapphire. When we fool the Light Sensor up
to Maximum Brightness, the Color Gamuts are still only 68% with Glass and 54%
with Sapphire at 2,000 lux. However, Full Daylight that is not in direct
sunlight ranges from 10,000 to 25,000 lux, and the Gamuts will continue to
decrease significantly with increasing ambient light. See the Color Gamut
with Ambient Light section and Figure 2 for measurements
and details.
Watch Viewing Angle Performance
For both the Sapphire and Glass displays we measured
similar small to medium shifts in Brightness and Color with Viewing Angles up
through 30 degrees. At much larger Viewing Angles sapphire shows larger shifts
than glass. See the Viewing
Angle Variations section for details.
Analyzing the Photo Below of the Watches in Ambient Light
The Lab tests quantitatively evaluate display performance
with measurements of a large number of display parameters using specialized
instruments and test patterns. Even if you like comparing Contrast Ratios,
Color Gamuts, and other parameters, it’s also nice to see a screen shot of the
displays under test to visually compare the results and differences.
The Photo below is a side-by-side
screen shot of the Apple Watch Sport with Ion-X Glass on the left, and the
Apple Watch with Sapphire on the right. They were taken together simultaneously
inside an Integrating Hemisphere that provides a very uniform light
distribution coming from all directions. The watches are sitting on a dark
black background.
Photo Caption with
Explanations
There are a number of important but subtle details that
we will explain first. The Apple Watch on the right has a mirror stainless
steel finish, so the lower portion of the case appears dark in the photo
because it is providing a mirror reflection of the black background. The Apple
Watch Sport on the left has anodized aluminum with a matte finish that diffusely
reflects light from all directions and therefore has a more uniform appearance.
So if you don’t look closely it looks as if the Apple Watch on the right is
smaller, but it’s just an optical illusion from the differing brightness
reflections from the cases. Also note that the mirror finish of the watch on
the right is reflecting the Digital Crown and Side Button of the watch on the
left.
In the dark both watches appear identical. The OLED
displays have a perfect all black background, with white text and graphics, and
a vibrant saturated red second hand.
The screen shot Photo below was
taken at an ambient light level of 2,000 lux, which corresponds to moderate
outdoor lighting in the shade or an overcast sky. Indoor residential lighting
typically ranges from 100 to 500 lux, while office, commercial, and task
lighting typically ranges 500 to 1,500 lux. Full Daylight that is not in direct
sunlight ranges from 10,000 to 25,000 lux, while direct sunlight is 120,000
lux. To see how other displays perform in up to 40,000 lux see this article on Displays
in High Ambient Light.
In the Photo below the ambient light
penetrates and reflects from different layers in the display so some of its
internal structures are visible. The OLED display itself is the inner rectangle
in both watches. The background is much brighter on the right Sapphire display
due to its 74% higher Reflectance compared to the Glass display on the left.
The reflected ambient light reduces the image contrast of the white text and
graphics, and also the color saturation and vibrancy of the red second hand.
The large differences between displays are very obvious and striking.
Finally, on a technical note, the slight green tint
visible in the photo for the Apple Watch with Sapphire on the right is due to a
variation in its Reflectance Spectrum for ambient light, which is stronger in
the green portion of the spectrum and weaker in the red and blue portions of
the spectrum compared to the Apple Watch Sport with Glass display on the left.
It is unlikely to be noticeable except possibly in high ambient light that is
itself neutral in color. This effect does not occur with pure sapphire, so it
is most likely due to something in the optical bonding and lamination of the
sapphire to the OLED display.
Apple Watch Sapphire vs Glass Display
Conclusions
The primary goal of this Display Technology Shoot-Out
article series has always been to publicize and promote display excellence
so that consumers, journalists and even manufacturers are aware of and
appreciate the very best in displays and display technology. We point out which
manufactures and display technologies are leading and advancing the
state-of-the-art for displays by performing comprehensive and objective
scientific Lab tests and measurements together with in-depth analysis. We point
out who is leading, who is behind, who is improving, and sometimes
(unfortunately) who is back pedaling… all based solely on the extensive
objective careful Lab measurements that we also publish, so that everyone can
judge the data for themselves as well… See the Display
Shoot-Out Comparison Table for all of the Lab measurements and testing
details, and the Results Highlights section above for
a more general overview with explanations.
Apple Watch OLED Display
The Apple Watches have an excellent state-of-the-art OLED
display that we analyzed in detail in our earlier Apple Watch OLED
Display Technology Shoot-Out article. Refer to that article for an in-depth
analysis of their OLED display.
Apple Watch and Apple Watch
Sport Displays
For this article we have compared and analyzed the
displays on the Apple Watch with a Sapphire
Crystal and the Apple Watch Sport with Ion-X
Glass. Both watches have the same OLED display, only the cover sapphire and
glass are different, resulting in a large difference in their Screen Reflectance
and performance in ambient light. One very important and significant result
from testing the two watch displays in the dark at 0 lux is that their
photometry and colorimetry calibration measurements were both very good to
excellent, and almost identical to one another, indicating a careful and
accurate systematic factory calibration – Apple typically has each display
individually calibrated. See the Brightness
and Contrast and Color Gamut
sections and Figure 1 for
measurements and details.
Different Screen Reflectance
In the dark both Apple Watch displays appear and perform
identically, but in ambient light they appear and perform differently due to
the difference in the Reflectance of Sapphire and Glass.
For the Apple Watch Sport with Ion-X Glass we measured
the Screen Reflectance to be 4.7 percent, while for the Apple Watch with
Sapphire we measured 8.2 percent Screen Reflectance, which is 74 percent higher
than Glass. Both values are about 0.6 percent higher than just pure sapphire
and glass alone, indicating that Apple has done an excellent job in optically
bonding both the glass and sapphire to the OLED display without an air gap. See the Reflections
section for measurements and details.
Both sapphire and glass each have many distinctive and
important properties besides the Reflectance, and what is particularly
interesting and relevant is that by using some new advanced technologies, the
Reflectance of not only Sapphire but also Glass will be reduced significantly
in the very near future for some displays, with major implications and
improvements for both the visual and optical display performance, which we will
discuss below.
Different Performance in
Ambient Light
The 74 percent higher Reflectance of the Apple Watch with
Sapphire means that its screen will reflect almost twice as much surrounding
ambient light as the Apple Watch Sport with Glass. And it takes surprisingly
little ambient light for that to make a visible difference…
Contrast Ratio:
While their Contrast Ratios are infinite at 0 lux
absolute darkness, they decrease rapidly with ambient light. At just 500 lux,
which is mid-range indoor ambient lighting, the display Contrast Ratios have
fallen to just 64 with Glass and 38 with Sapphire (with the displays set to
their Maximum Brightness of about 480 nits by fooling the Ambient Light Sensor,
otherwise it is less than half the values). That’s indoors…
At an ambient light level of 2,000 lux, which corresponds
to moderate outdoor lighting in the shade or an overcast sky, the display
Contrast Ratios are just 17 with Glass and 10 with Sapphire (again with the
displays set to their Maximum Brightness by fooling the Ambient Light Sensor,
otherwise it is about 70% of the values). However, Full Daylight that is not in
direct sunlight ranges from 10,000 to 25,000 lux – for 10,000 lux the Contrast
Ratios are 3 and 2 respectively. See the Brightness
and Contrast with Ambient Light section for measurements and details.
Color Gamut and Color
Saturation:
While their Color Gamuts are both close to 100% of the
sRGB/Rec.709 Standard Gamut at 0 lux absolute darkness as shown in Figure 1, they also
decrease with ambient light. At just 500 lux, the Color Gamut is 93% with Glass
and 85% with Sapphire (with the displays set to their Maximum Brightness of
about 480 nits by fooling the Ambient Light Sensor, otherwise it is about 15%
less), as shown in Figure 2.
That’s indoors…
At an ambient light level of 2,000 lux, which corresponds
to moderate outdoor lighting in the shade or an overcast sky, the Color Gamuts
are just 68% with Glass and 54% with Sapphire (again with the displays set to
their Maximum Brightness by fooling the Ambient Light Sensor, otherwise it is
about 80% of the values). See the Color Gamut
with Ambient Light section and Figure 2 for measurements
and details.
Photo of the Displays in
Ambient Light:
The Lab measurements like the Contrast Ratios and Color
Gamuts above quantitatively evaluate display performance, but it’s also nice to
see a screen shot of the displays under test to visually compare the results
and differences. The Photo Above or this Photo Link is a
side-by-side screen shot of the Apple Watch Sport with Ion-X Glass on the left,
and the Apple Watch with Sapphire on the right. They were taken together
simultaneously inside an Integrating Hemisphere that provides a very uniform
light distribution coming from all directions at an ambient light level of
2,000 lux, which corresponds to moderate outdoor lighting in the shade or an
overcast sky. See the Caption or the Photo Link for a detailed
explanation of the photo.
Lowering the Reflectance of
Sapphire and Glass
The standard way that has generally been used to improve
display performance in ambient light is to fight fire-with-fire and just
continue increasing the display’s Maximum Brightness. But there is a practical
limit to that, plus a brighter display needs more power and a bigger battery.
Clearly the best (and smartest) way to improve display performance, image
contrast, color saturation, screen visibility and readability in ambient light
is to lower the Screen Reflectance. In fact, it is the
only way to turn the marginal Yellow Contrast and Gamut measurement
results in the Display
Shoot-Out Comparison Table into Green Very Good to Excellent performance
levels. Plus, if you do that, the same display can be used at a lower
Brightness setting, which will decrease the display power and increase the running
time on battery.
In order to increase the use of sapphire for displays,
the sapphire industry will need to modify the optical properties of sapphire
without significantly affecting its scratch resistance and other mechanical
properties. It can’t be done using traditional Anti-Reflection optical coatings
which scratch easily.
With some new advanced technologies that will be
introduced soon, the Reflectance of not only Sapphire but also Glass will be
reduced significantly for some displays, and they will be available in the very
near future, with major implications and improvements for both visual and
optical display performance.
We will provide more information on Low Reflectance
Sapphire and Glass in our upcoming 2015 Innovative
Displays and Display Technologies article. Here is a link to the 2014 Edition.
Follow DisplayMate on Twitter
to learn about these developments and our upcoming display technology coverage.
The Next Steps in Display
Performance Improvements in Ambient Light
Lowering
the Screen Reflectance is just the first step in the upcoming major
improvements of display performance in ambient light. The next steps will
include using very wide Color Gamuts together with Dynamic Color Management and
a Dynamic Intensity Scale that are both automatically adjusted real-time based
on the measured current Ambient Light level in order to have them compensate
for the reflected light glare and image wash out from ambient light as
discussed above and in our 2014
Innovative Displays and Display Technology article.
All of these results and conclusions apply to all
displays that are used in ambient light, including smartphones, smart watches,
tablets, laptops, PC and video monitors, even TVs (if you watch during the day
or with room lights on at night), and especially for displays that are mostly
used in outdoor environments like digital signage and automobile displays.
The
displays, technologies, and manufacturers that succeed in implementing these
new high ambient light display performance strategies will take the lead in the
next generations of displays… Follow DisplayMate on
Twitter to learn about these developments and our upcoming display
technology coverage.
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The Apple Watches in Ambient Light
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Display
Shoot-Out Comparison Table
Below we
examine in-depth the relative display performance of the Apple Watch that has a
Sapphire Crystal with
the
display on the Apple Watch Sport that has
an Ion-X Cover Glass, using objective Lab measurement data and criteria.
The
displays on both Apple Watches have the same OLED display with identical
specifications except for the outer display cover, which is either Sapphire or
Ion-X Glass and results in significant differences in optical performance that
are analyzed below. For an in-depth analysis of the OLED display on Apple Watch
display see our earlier
Apple Watch
OLED Display Technology Shoot-Out article.
For
additional information on OLED display measurements see our Galaxy S6
Display Technology Shoot-Out article.
For
comparisons with Samsung and Sony Smart Watches see our Smart Watch
Display Technology Shoot-Out article.
For
comparisons with the other leading displays including LCDs see our Mobile Display Technology
Shoot-Out series.
Categories
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Apple Watch 42 mm
with Sapphire Crystal
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Apple Watch Sport 42 mm
with Ion-X Glass
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Display Technology
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Flexible OLED
RGB Stripe
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Flexible OLED
RGB Stripe
|
Display Shape
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4:5 = 0.80
Portrait Only
|
4:5 = 0.80
Portrait Only
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Display Size
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1.53 inches Diagonal
1.21 x 0.97 inches
with rounded corners
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1.53 inches Diagonal
1.21 x 0.97 inches
with rounded corners
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Display
Area
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1.2 square inches
|
1.2 square inches
|
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Relative
Display Area
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100 percent
|
100 percent
|
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Display
Resolution
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390 x 312 pixels
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390 x 312 pixels
|
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Total
Number of Pixels
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122K pixels
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122K pixels
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Pixels
Per Inch
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322 ppi
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322 ppi
|
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20/20
Vision Distance
where
Pixels are Not Resolved
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10.7 inches
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10.7 inches
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Appears
Perfectly Sharp
at
Typical Viewing Distances
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Yes
Apple Retina Display
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Yes
Apple Retina Display
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Text
and Graphics
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Very Sharp
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Very Sharp
|
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Display
Color Depth
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Full 24-bit color
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Full 24-bit color
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Screen Reflections
The
Screen Reflects Ambient Light, which washes out the Image Contrast and
Colors.
The
Average Reflectance is measured with an Integrating Hemisphere and
Spectroradiometer.
The
Mirror Reflections are measured with a highly collimated beam of light and
Spectroradiometer.
The
Reflectance of Sapphire is much higher than Glass.
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Average Screen Reflection
Light
from All Directions
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with Sapphire
8.2 percent
Good
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with Glass
4.7 percent
Excellent
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Relative Brightness of the
Reflected Ambient Light
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174 percent
Reflections Much Stronger
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100 percent
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Mirror Reflections
Percentage
of Light Reflected
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with Sapphire
9.2 percent
Good
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with Glass
5.7 percent
Very Good
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Contrast Rating for
High Ambient Light
The Higher the Better
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with Sapphire
Up to 59 Good
Automatic Light Sensor
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with Glass
Up to 101 Very Good
Automatic Light Sensor
|
|
Apple Watch with Sapphire
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Apple Watch Sport with Glass
|
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Brightness and Contrast with Ambient Light
At
0 degrees Viewing Angle.
But
the typical Viewing Angle for a Watch is actually 30 degrees or more. See
below.
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Maximum Brightness
Measured
in the dark at 0 lux
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Up to 482 cd/m2
Automatic Light Sensor
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Up to
473 cd/m2
Automatic Light Sensor
|
|
Black Brightness at 0 lux
at
Maximum Brightness
|
0 cd/m2 at 0 lox
Increases with Ambient
Light
|
0 cd/m2 at 0 lux
Increases with Ambient
Light
|
Contrast Ratio
Measured
in the dark at 0 lux
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Infinite at 0 lux
Decreases with Ambient
Light
|
Infinite at 0 lux
Decreases with Ambient
Light
|
|
|
Auto Brightness Level
Measured
in Ambient Light
Maximum
Brightness Setting
|
with Automatic Light
Sensor
203 cd/m2 at 500
lux
290 cd/m2 at 2,000
lux
482 cd/m2 at High
lux
|
with Automatic Light
Sensor
217 cd/m2
at 500 lux
323 cd/m2 at 2,000
lux
473 cd/m2 at High
lux
|
Contrast Ratio
Measured
in Ambient Light
Maximum
Brightness Setting
|
with Automatic Light
Sensor
17 at 500 lux
7 at 2,000 lux
with Maximum Brightness
38 at 500 lux
10 at 2,000 lux
|
with Automatic Light
Sensor
29 at 500 lux
12 at 2,000 lux
with Maximum Brightness
64 at 500 lux
17 at 2,000 lux
|
Relative Contrast Ratio
|
59 percent
Contrast Significantly
Lower
|
100 percent
|
|
Apple Watch with Sapphire
|
Apple Watch Sport with Glass
|
|
Color Gamut with Ambient Light
The
Image Colors depend on the Ambient Light and Viewing Angle.
|
Color of White
Color
Temperature in degrees
Measured
in the dark at 0 lux
|
7,145 K
Slightly Too Blue
Lower OLED Power
Efficiency
|
7,085 K
Slightly Too Blue
Lower OLED Power
Efficiency
|
Color Gamut
Measured
in the dark at 0 lux
See Figure 1
|
104 percent at 0 lux
sRGB / Rec.709
Decreases with Ambient
Light
See Figure 1
|
107 percent at 0 lux
sRGB / Rec.709
Decreases with Ambient
Light
See Figure 1
|
Color Gamut
Measured
in Ambient Light
See Figure 2
|
with Automatic Light
Sensor
69 percent at 500 lux
39 percent at 2,000 lux
with Maximum Brightness
85 percent at 500
lux
54 percent at 2,000 lux
See Figure 2
|
with Automatic Light
Sensor
82 percent at 500 lux
58 percent at 2,000 lux
with Maximum Brightness
93 percent at 500 lux
68 percent at 2,000 lux
See Figure 2
|
Relative Color Gamut
|
Gamut Significantly
Smaller
|
Gamut Significantly
Better
|
|
Apple Watch with Sapphire
|
Apple Watch Sport with Glass
|
|
Viewing Angle Variations
The
typical Viewing Angle for a Watch is actually about 30 degrees or more from
exactly face on.
See this Figure for an explanation and visual
definition of JNCD.
|
Brightness Decrease
at a 30
degree Viewing Angle
|
with Sapphire
32 percent
Medium Decrease
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with Glass
32 percent
Medium Decrease
|
Black Level Change
at a 30
degree Viewing Angle
|
0 percent
No Change for OLED
|
0 percent
No Change for OLED
|
White Point Color Shift
at a 30
degree Viewing Angle
|
Small Color Shift
Δ(u’v’) = 0.0102
2.5 JNCD
with Sapphire
|
Small Color Shift
Δ(u’v’) = 0.0099
2.5 JNCD
with Glass
|
Color Shifts
Primary
Colors and Mixtures
at a 30
degree Viewing Angle
|
Medium Color Shift
Largest Shift Δ(u’v’) = 0.0375
9.4 JNCD with
Sapphire
|
Medium Color Shift
Largest Shift Δ(u’v’) = 0.0397
9.9 JNCD with
Glass
|
Categories
|
Apple Watch 42 mm
with Sapphire Crystal
|
Apple Watch Sport 42 mm
with Ion-X Glass
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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, HDTVs, 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 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. 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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