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Ergonomic Design Guidelines for
Flat Panel Display Televisions
Special Committee on FPD-TV Ergonomics
Japan Ergonomics Society
Special Committee on FPD-TV Ergonomics in Japan Ergonomics Society
List of the committee members (in kana order of family name)
Yoichi Igarashi Panasonic LCD Co.,Ltd.
Kazuhiko Inoguchi Sharp Corp.
Naoaki Umezu Toshiba Corp.
Kazuyuki Kishimoto Sharp Corp.
Hiroki Kitajima The Institute for Science of Labour
Chair Satoru Kubota Seikei University
Seiichi Goshi Kogakuin University
Susumu Saito The Institute for Science of Labour
Tokihiko Shinomiya Sharp Corp.
Masanori Takemoto Seikei University
Takehiro Nakatsue Sony Corp.
Yoshitomo Nakamura Mitsubishi Electric Corp.
Shuichi Haga Sony Corp.
Hisatake Yuuzo Toshiba Mobile Display Co.,Ltd.
Tatsuhiko Matsumoto Sony Corp.
Yoshitaka Yamamoto Sharp Corp.
Ryoji Yoshitake IBM Japan
Ergonomic design guidelines for flat panel display televisions
Japan Ergonomics Society
All rights reserved
Published: January, 2012
Contents
1. Introduction ・・・・・・・・・・・・・・・・・・・・・・・・・・1
2. Intended audience ・・・・・・・・・・・・・・・・・・・・・・・1
3. Contents ・・・・・・・・・・・・・・・・・・・・・・・・・・・1
4. Perspectives on ergonomic design for flat panel televisions ・・・・・2
5. Display luminance ・・・・・・・・・・・・・・・・・・・・・・・3
(1) Screen illuminance 4
(2) Screen visual angle 6
(3) Average luminance level 7
(4) Multiple regression models of optimum display luminance 8
(5) Effects of aging on optimum display luminance 10
6. Black level luminance ・・・・・・・・・・・・・・・・・・・・・12
7. Luminance contrast ・・・・・・・・・・・・・・・・・・・・・・13
8. White point (color temperature) ・・・・・・・・・・・・・・・・15
(1) Preferred color temperature 15
(2) Effects of aging 18
9. Viewing distance ・・・・・・・・・・・・・・・・・・・・・・・19
10. Display height ・・・・・・・・・・・・・・・・・・・・・・・・22
11. Screen tilt angle ・・・・・・・・・・・・・・・・・・・・・・・24
(1) Optimum tilt angle 24
(2) Minimize screen glare by tilting screen 26
12. Viewing angle ・・・・・・・・・・・・・・・・・・・・・・・・30
13. Conclusions ・・・・・・・・・・・・・・・・・・・・・・・・・33
References ・・・・・・・・・・・・・・・・・・・・・・・・・・・・34
Annex
Results of Web questionnaire survey on viewing conditions of
LCD televisions at home ‐ A comparison of six countries ‐
(Brazil, China, India, Japan, the United Kingdom, and the United
States) ・・・・・・・・・・・・・・・・・・・・・・・・・・・・39
These guidelines are based on the results of laboratory experiments and field
surveys, which were supported by NEDO (New Energy and Industrial Technology
Development Organization)
Ergonomic Design Guidelines for Flat Panel Display Televisions
Japan Ergonomics Society 1
1. Introduction
Cathode ray tube (CRT) televisions are rapidly being replaced by large flat panel LCD
and plasma televisions that support high-definition digital broadcasts. Development of high
definition television (HDTV) began after the 1964 Tokyo Olympics, with the first standard
proposed in 1972 by the International Telecommunication Union (ITU), formerly the
Consultative Committee on International Radio (CCIR). Based on experimental research
performed at that time, initial ergonomic specifications were established for items such as
screen visual angle, aspect ratio, viewing distance, and resolution1)–6). Because that research
predominantly used static images projected from film, however, and broadcasters, not
manufacturers, developed the proposed standard, certain ergonomic design issues that arise
during actual television viewing were likely not taken into consideration. Given the recent
full transition to digital terrestrial broadcast and trends toward viewing television on
state-of-the-art large flat panel displays, new ergonomic design guidelines that take into
consideration current television viewing environments are needed.
Establishment of such guidelines would not only provide viewers with better conditions
for watching flat panel televisions, but also contribute to lowering energy consumption7), 8).
Ergonomic design guidelines benefit television manufacturers by promoting healthy
development of display technologies, and benefit consumers through the establishment of
conditions for comfortable home television viewing with lower energy costs.
2. Intended audience
These Guidelines were created as a reference for television engineers (including those
performing work related to displays, image processing, image quality evaluation, appliance
design, quality control, etc.) to design and develop flat panel televisions in accordance with
ergonomic considerations that will allow viewers to watch television in appropriate,
comfortable conditions. These Guidelines are also intended to serve as a reference for
content creators, broadcasters, and broadcast technicians in regard to the actual viewing
conditions under which televisions are best watched.
3. Contents
Display luminance .................................................................................... Section 5
Black level luminance .............................................................................. Section 6
Luminance contrast .................................................................................. Section 7
Screen white point (color temperature) .................................................... Section 8
Viewing distance ...................................................................................... Section 9
Display height ........................................................................................ Section 10
Ergonomic Design Guidelines for Flat Panel Display Televisions
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Screen tilt angle ...................................................................................... Section 11
Viewing angle ......................................................................................... Section 12
4. Perspectives on ergonomic design for flat panel televisions
One of the most important goals of ergonomics is human-centric product design. Such
design requires a firm understanding of the conditions under which the product will be used,
and design optimization that will maximize user satisfaction. Many product specifications
are mutually related, meaning that ergonomic design must be comprehensively
implemented from the initial stages of product development. Figure 1 shows an overview
of ergonomic design for flat panel televisions.
First, designers must have a sufficient understanding of the viewing environment. When
designing display luminance, luminance contrast, and color reproduction, for example,
lighting conditions affect not only viewer adaptation to luminance and color, but also the
display itself. Survey data related to viewing distance and angle are also vital when
designing features related to display luminance and viewing angle. These Guidelines
provide a wide scope of data related to home television viewing environments and
conditions, and furthermore provide conditions for maximizing viewer satisfaction based
on multifaceted laboratory experiments.
Figure 1. Overview of flat panel television ergonomic design.
Display luminance Luminance contrast Black level Color reproduction White point Viewing angle dependence Gray scale Frame rate Motion artifacts, etc.
Display(image
properties)
Displaycontents
Viewer
Viewingenvironment
Evaluation criteria
・Preference・Pleasantness・Visual fatigue・Total image
quality
Lighting environment・Screen illuminance・Color temperature of ambient light
Viewing distance Screen visual angle Viewing direction Disturbing reflections of
ambient light sources, etc.
Content genre Average luminance level Gamut Moving characteristics Angle of view, etc.
Vision・Visual acuity・Color sensitivity・Accommodation・Contrast sensitivity
Age Individual variation Gender Viewing time, etc.
Subjective evaluation・Rating scale method・Pairwise comparison method・Ranking method, etc.
Psychophysical evaluation・Method of adjustment・Method of limits, etc.
Ergonomic Design Guidelines for Flat Panel Display Televisions
Japan Ergonomics Society 3
Second, characteristics of the displayed image must be known. For example, required
luminance and luminance contrast values are strongly influenced by the image’s average
luminance level (ALL) after gamma correction. These Guidelines analyze terrestrial digital
broadcast signals and find statistical values for ALL to allow for consideration of such
characteristics.
Third, the influence of viewer characteristics, particularly visual characteristics, must be
taken into consideration. Given the ongoing aging of society in many countries, changes in
vision that occur with increased age are of particular concern. Even among individuals
within a particular age group there is significant variation in optimal settings for various
design elements, and consideration of how technology can adapt to such variation is
another topic for ergonomic design. These Guidelines were designed to allow reference to
the distributions, standard deviations, and percentiles for such data.
Finally, there is a need to assess the above factors through experiments with a variety of
participant groups. Where possible, such assessments should involve at least 15 participants
who are not display experts for each study. Factors related to the ergonomic design of flat
panel televisions such as preference, comfort, fatigue, and overall image quality require
quantification using methods from psychological evaluation such as ratings scales and
pairwise comparisons. For some design elements, psychophysical experimentation methods
such as methods of limits and adjustment may be applied.
When presenting guidelines for design elements, these Guidelines use perspectives such
as those described above to describe viewing environments and conditions. Note that these
Guidelines were developed using survey results obtained within Japan, and therefore may
not be applicable to the use of flat panel televisions in overseas markets. The fundamental
perspective of these Guidelines, however, is applicable to the design of flat panel
televisions in any country. To that end, we have included as an annex the results of surveys
related to flat panel television viewing from six countries (Brazil, China, India, Japan, the
United Kingdom, and the United States). Comparison of differences in television viewing
environments between Japan and other countries should allow for the application of the
Guidelines to the design of flat panel televisions for overseas markets.
5. Display luminance
Television screen settings related to appropriate display luminance are important for
reducing visual discomfort and energy consumption. Excessive luminance not only
increases the risk of visual fatigue9)–11), but also wastes electricity7), 8).
As shown in Figure 2, optimum display luminance depends on a number of factors,
including ambient luminance, angular screen size, ALL after gamma correction, and viewer
age7), 8), 12)–17). Here, we define optimum display luminance as the white luminance
Ergonomic Design Guidelines for Flat Panel Display Televisions
4
(including components of reflected luminance) after the viewer has adjusted the display
luminance to the most preferred brightness when a particular image is displayed.
Ambient illuminance determines the viewer's luminance adaptation level, and also
affects black level luminance and luminance contrast. When designing displays, the
influence of ambient illuminance is estimated by taking screen illuminance as the vertical
plane illuminance incident to the screen.
Figure 2. Primary factors affecting the optimum display luminance of television screens.
(1) Screen illuminance
Figure 3 shows the distribution of screen illuminance settings for televisions in living
rooms in Japan7), 8). The distribution is based on per-minute measurements of powered-on
televisions in 77 households, combining daytime and nighttime measurements. Values are
20 lx at the 10th percentile, 92 lx median, and 305 lx at the 90th percentile. Appropriate
display luminance should be adjustable according to this illuminance distribution. Figures 4
and 5 show screen illuminance distributions divided between daytime and nighttime
measurements, respectively. The respective mode values (78 lx and 71 lx) are nearly
identical, but median values are 123 lx for daytime and 74 lx for nighttime, and 90th
percentile values are 518 lx and 140 lx, respectively.
It is furthermore necessary to allow adjustment of appropriate display luminance while
viewing in low illumination or dark environments, such as found in home theaters. As
shown in the Annex, while only 1% of Japanese households view television with lights
turned off, 10% of households in Western countries do so18).
Another factor related to appropriate display luminance is the effects on viewing
luminance from areas behind the screen, which is related to screen illuminance. In a typical
Optimum display luminance(ODL)
Spatial viewing conditions
Image content
Environmental illumination
Viewer characteristics
ASL/ALL
Viewing distance /Screen visual angle
Viewer age / Age-related changes
Screen illumination /Visual field luminance
Ergonomic Design Guidelines for Flat Panel Display Televisions
Japan Ergonomics Society 5
living room, the average nighttime luminance in a 180° view excluding the television
screen is 5 cd/m2 for a screen illuminance of 30 lx, and similarly 17 cd/m2 at 100 lx, and 50
cd/m2 at 300 lx7). This is equivalent to a behind-screen wall with a reflectance of 60% (N8).
As described in the Annex many households in Japan have televisions positioned facing
away from south-facing windows19), making it difficult to use screen illuminance to predict
the luminance of visual field during daytime television viewing20).
Figure 3. Screen illuminance with television on, based on per-minute
measurements over 24 h in 77 households.
Figure 4. Daytime screen illuminance with Figure 5. Nighttime screen illuminance with television on, based on per-minute television on, based on per-minute
measurements over 24 h in 77 households. measurements over 24 h in 77 households.
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Distribution of screen illuminance with television on (77 households over 24 hours)
Mode 71 Unit:lxGeometric mean 84Median 92Mean 17210th percentile 2090th percentile 305Min. 0.1Max. 42600
Full day
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Distribution of screen illuminance with television on (77 households over 24 hours)
Mode 78 Unit:lxGeometric mean 116Median 123Mean 25710th percentile 2790th percentile 518Min. 0.53Max. 42600
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Distribution of screen illuminance with television on (77 households over 24 hours)
Mode 71 Unit:lxGeometric mean 61Median 74Mean 8610th percentile 1590th percentile 140Min. 0.05Max. 1167
Nighttime
Ergonomic Design Guidelines for Flat Panel Display Televisions
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(2) Screen visual angle
The screen size and the viewing distance determine the screen visual angle. Table 1
shows the relationship between the screen visual angle (deg), relative viewing distance (H:
screen height), and viewing distance (cm). Figure 6 shows the viewing distance for
televisions in Japanese living rooms7), 21), for which the 10th percentile is 165 cm, the
median is 252 cm, and the 90th percentile is 417 cm. The viewing distance depends more
on room size and placement of sofas and other furniture than on screen size7), 22), 23). It is
therefore necessary to select an appropriate screen size for the viewing distance. In Section
9, the preferred viewing distance for each screen size is discussed.
Figure 7 shows a graph of measurement results for various screen sizes. Here,
measurements were performed by seating a household member in the most preferred
position for television viewing and measuring the horizontal visual angle to the television
(angular size in degree). A 3H (three times the screen height) relative viewing distance
gives a horizontal visual angle of 33°, but the data show that most households view
television from a greater distance. Screen sizes around 40 in. had visual angles of around
15° to 30°, with an average of approximately 20°. As shown in Table 1, a horizontal visual
angle of 20° is equivalent to a viewing distance of 5H. When viewing a 40-in. screen from
about 250 cm away, the display angle is 20°.
Table 1. Relationship between horizontal visual angle (deg), relative viewing distance (H), and viewing distance (cm). Screen aspect ratios were 16:9.
24 in. 32 in. 40 in. 46 in. 55 in. 65 in.
10 10.2 304 405 506 582 696 822
12 8.5 253 337 421 484 579 685
14 7.2 216 288 361 415 496 586
16 6.3 189 252 315 362 433 512
18 5.6 168 224 280 321 384 454
20 5.0 151 201 251 289 345 408
22 4.6 137 182 228 262 313 370
24 4.2 125 167 208 240 286 338
26 3.9 115 153 192 221 264 312
28 3.6 107 142 178 204 244 289
30 3.3 99 132 165 190 227 269
32 3.1 93 124 154 178 212 251
34 2.9 87 116 145 167 199 235
36 2.7 82 109 136 157 187 221
38 2.6 77 103 129 148 177 209
40 2.4 73 97 122 140 167 198
Horizontalvisual
angle (deg)
Relativeviewing
distance (H)
Viewing distance (cm)
Ergonomic Design Guidelines for Flat Panel Display Televisions
Japan Ergonomics Society 7
Figure 6. Viewing distance distribution for 393 members of 83 households.
Figure 7. Relationship between diagonal screen size (in.) and horizontal visual angle (deg) for the most preferred television viewing positions in 83 households.
(3) Average luminance level
After a device receives a broadcast image signal, it applies gamma correction based on
the gamma value of the received image, and converts the results to an ALL that takes a
fully white screen as a relative value of 100. A typical decoded gamma is approximately 2.2.
The ALL of an image varies with the type of broadcast, but analysis of terrestrial digital
broadcasts of five Japanese channels for one week resulted in an overall average of
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83 householdsN=393Median=252Mean=27710%ile=16590%ile=417Max=674Min=108
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LCD N=32
CRT N=41
PDP N=10
Ergonomic Design Guidelines for Flat Panel Display Televisions
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approximately 25%. Figure 8 shows a distribution of ALL values for all broadcast frames
from the five major Japanese television stations during one week in 200924). The 5th
percentile is 5%, and the 95th percentile is 44.8%. Average signal level (ASL) before
gamma correction was 44.8% overall, and 45.9% during prime time, approximately the
same as ALL values recorded over 200 days of satellite broadcasts25). Note, however, that
average luminance may be higher for television shows broadcast in Japan; when overall
ASL was measured over 40–60 h of broadcasts in the United States, the United Kingdom,
Australia, France, and Japan as part of establishing measurement methods for the television
power consumption measures of IEC 6208726), the obtained value was 34%, approximately
10% lower than the Japanese case. Data on viewing frequencies of shows by broadcast type
are included as the Annex. As compared with other countries, viewership of variety shows
is particularly high in Japan, as is their frequency of broadcast. In the United States,
viewership of movies is the highest. The relatively high ASL values seen in Japan may be
due to such differences in broadcast genre preferences.
Figure 8. Distribution of ALL values for all broadcast frames from the five major Japanese television stations (data measured between July 31 and August 7, 2009).
(4) Multiple regression models of optimum display luminance
To find optimum display luminance (ODL) values we performed multifactor laboratory
experiments with participants of various ages, using the above-described screen
illuminance, visual angle, and image ALL as test variables7), 8), and found a double
logarithmic, linear relationship between each of these three factors and ODL. With respect
to ODL, as each factor acts independently, we were also able to derive a multiple
regression model to predict ODL. Here, ODL refers to the white luminance (including
0.0%
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cy[H
isto
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bin
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th is
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%]
Image average luminance level (ALL) (%)
NHK-GNippon TelevisionTBSFuji TelevisionTV Asahi
Overall average= 25 %5th percentile= 5 %
10th percentile= 8 %90th percentile= 45 %95th percentile= 51 %
Ergonomic Design Guidelines for Flat Panel Display Televisions
Japan Ergonomics Society 9
components of reflected luminance) during display of a specific image with display
luminance set to the viewer’s most preferred brightness.
Equation (1) is the model for a participant group with average age 22. Equation (2) is a
similar model for elderly viewers, created using a participant group with average age 71.
These models were found from the geometric mean of values from 24 participants from
each age group, so that ODL distributions would be lognormal under each test condition as
set by the participants. In terms of geometric standard deviations, variation between
participants was approximately 0.6 times the geometric mean at the –1 standard deviation
level, and 1.7 times the geometric mean at the +1 standard deviation level. In other words,
approximately 68% of test results should fall within this range. For example, given an ODL
of 100 cd/m2, roughly 68% of participant data should fall within the range 60–170 cd/m2.
Such individual differences should be taken into consideration when designing the range
over which display luminance can be adjusted.
• ODL regression model for young group (average age 22).
log PL=2.40+0.27 log E-0.22 log SA-0.32 log AL (1)
(F(3,23)=1051, p<0.001, R2=0.99)
• ODL regression model for elderly group (average age 71).
log PL=2.87+0.13 log E-0.34 log SA-0.21 log AL (2)
(F(3,23)=141, p<0.001, R2=0.94)
Here, PL is the ODL (cd/m2), E is the screen illuminance (lx), SA is the horizontal visual
angle (deg), and AL is the image ALL (%).
Figure 9 is a contour map based on the young group ODL model of Equation (1),
showing ODL (white luminance) according to screen illuminance and visual angle when
ALL is taken as the 25% average level of general broadcasts. Figure 10 similarly uses the
elderly group ODL model of Equation (2).
Figure 11 shows ratios of elderly to young ODL values, indicating the differences in
ODL between young and elderly viewers under the various conditions. Of particular note is
that the differences between young and elderly viewers increase as screen illuminance
values and visual angles decrease.
Ergonomic Design Guidelines for Flat Panel Display Televisions
10
Figure 9. ODL by screen illuminance Figure 10. ODL by screen illuminance and screen visual angle, young group and screen visual angle, elderly group (average age 22) for 25% ALL. (average age 71) for 25% ALL.
Figure 11. Ratio of elderly and young participant ODL for screen illuminance and screen visual angle (ratio of values from Figures 9 and 10).
(5) Effects of aging on optimum display luminance
Figure 12 shows the ODL values after performing a similar experiment with a wide
range of ages. These values were obtained with screen illuminance values of 30, 100, and
300 lx, the actual average horizontal visual angle of 20° (5H at the viewing distance), and
ALL of 25%. The figure shows that as age increases ODL increases linearly, indicating the
necessity of allowing setting of display luminance according to user age. As described
above, there are furthermore significant differences in ODL among individuals. Table 2
100
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140 160
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30 100 300
Hori
zon
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al an
gle
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Screen illuminance (lx)
cd/m2Young group (average age 22)ALL 25 %
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Ergonomic Design Guidelines for Flat Panel Display Televisions
Japan Ergonomics Society 11
summarizes the geometric mean and geometric standard deviation for ODL values, a
summary that is possible because ODL closely follows a lognormal distribution.
Approximately 68% of participants will fall within the range of ±1 geometric standard
deviations. These values for individual variation should be considered when setting the
range of luminance adjustments.
Figure 12. Television ODL as a function of age, under typical real-world viewing conditions of 20° horizontal angle (5H viewing distance) and 25% ALL.
Table 2. Television ODL (white luminance) by age, for actual viewing conditions of 20° horizontal angle (5H viewing distance) and 25% ALL. Because ODL closely follows a lognormal distribution, values are given as geometric means and geometric standard deviations (GSD). Approximately 68% of participants will fall within the range of ±1 GSD.
-1GSDGeometric
mean+1GSD -1GSD
Geometricmean
+1GSD -1GSDGeometric
mean+1GSD
20s 71 118 201 96 160 273 129 215 365
30s 83 138 234 109 182 309 140 234 398
40s 91 152 258 118 197 334 148 247 419
50s 101 168 286 128 214 363 157 261 444
60s 117 195 332 144 241 409 170 283 482
70s 127 211 359 154 256 436 177 296 503
Units:cd/㎡
Agegroup
Screen illuminance(lx)
30 100 300
50
500
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imu
m d
ispl
ay l
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wh
ite
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ce (
cd/㎡
)
Age
Screen illuminance 300 lx Screen illuminance 100 lx Screen illuminance 30 lx
100
200
300
400
Viewing angle 20 degALL 25 %
Ergonomic Design Guidelines for Flat Panel Display Televisions
12
6. Black level luminance
Black level luminance is an important factor in high-quality image display. The level of
black level luminance required to prevent the “floating black” effect depends on the image
content and environmental lighting conditions27). The conditions that result in the lowest
black level luminance demands are a full black screen under low illumination28). In other
words, if the floating black effect does not arise under these conditions, then it will not for
any image displayed. Figure 13 shows the results of testing using a 32-in. LCD television
in a nighttime family living room environment29). The values indicate the black level
luminance that does not result in floating blacks when viewing an all-black screen from a
3H viewing distance. Here, laboratory walls were covered with N8 (60% reflectance) cloth,
similar to conditions commonly found for walls behind televisions in residential living
rooms. To minimize the effects of reflected luminance components due to specularity of the
screen, the area in front of the screen (viewer’s side) was covered with black velveteen
cloth, allowing for almost no difference between antiglare and clear processed surfaces. A
test participant viewed an LCD television through a hole cut in the center of the cloth and
adjusted LCD backlighting until floating blacks were no longer perceptible thereby finding
the appropriate black level luminance value. Figure 13 shows the black level luminance
values that were the target of this experiment.
Figure 13. Luminance values at which floating blacks are not detectible for a full screen black display. Values are geometric means and percentiles for 21 individuals viewing a 32-in. LCD television from 3H (33° horizontal angle). Wall behind the screen is N8 (60% reflectance), the approximate average of living room walls.
y = 0.0087x0.61
R² = 0.99
y = 0.0039x0.70
R² = 0.99
y = 0.0252x0.47
R² = 0.96
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Geometric mean of 21 subjects5th percentile95th percentile
0.02
0.03
0.05
0.2
0.3
0.5
20 30 50 200 300 500
3.7 5.0 14.3 25.9 49.4 Average luminance of visual field(cd/㎡)
Ergonomic Design Guidelines for Flat Panel Display Televisions
Japan Ergonomics Society 13
The black level luminance required during image display also depends on the ALL of
the image itself, so it is not necessary to lower luminance to these values for every image27).
For television displays, the ratio of black level luminance and white luminance is often
taken as the contrast for device specifications. Using ODL levels as a basis of evaluation
can allow for dynamic range display luminance to meet display demands. Luminance
contrast is discussed in the following section.
7. Luminance contrast
The luminance contrast required for a television display can be defined as the ratio
between the ODL and the black luminance level required to prevent floating blacks on an
all-black screen under a given set of viewing conditions. This means that the display
luminance required for a display will dynamically change according to current conditions,
and that the ratio of the minimum and maximum luminance for a specific image cannot be
used. Table 3 shows the values for luminance contrast required for a display with an ODL
as discussed in Section 5, and a black level luminance that does not result in floating blacks,
as discussed in Section 6 (values are the former divided by the latter). In the case of
transmissive LCD televisions, these values are the luminance contrast required by the panel
with no backlight control.
Under 10th percentile screen illuminance (20 lx) and 5th percentile average luminance
for a typical broadcast (5% ALL), the required luminance contrast is approximately 3200.
Figure 14 shows a graph of needed luminance contrasts according to screen illuminance
and the ALL of a displayed image. When ALL and ambient illuminance are low, the
required contrast is high, but under actual viewing conditions, 5- and 6-figure luminance
contrasts are somewhat over-engineered from an ergonomics standpoint. Note, however,
that here we have not taken into consideration the reliance of display and black level
luminance on viewing angle. Section 12 discusses dependence of display characteristics on
viewing angle.
Ergonomic Design Guidelines for Flat Panel Display Televisions
14
Table 3. Required luminance contrast for given screen illuminance and image ALL. Required luminance contrast = ODL/black-screen luminance required to prevent
floating blacks.
Figure 14. Required luminance contrast by screen illuminance and image ALL. Required luminance contrast is the ratio of the black luminance required to prevent floating
blacks on an all-black display and the ODL (white luminance) for each ALL image.
100
1000
10000
1 10 100 1000
Req
uir
ed lu
min
ance
con
tras
t
Screen illuminance (lx)
5%
25%
51%
Average luminance level (ALL) of displayed image
200
300
500
2000
3000
5000
Black levelluminance requiredto prevent floating
blacks
Luminance for anall-black screen
(cd/m2)
5 25 51 5 25 51
A B C D A/D B/D C/D3 104 62 50 0.017 6100 3600 290010 145 86 69 0.035 4000 2400 190020 174 104 83 0.054 3200 1900 150030 195 116 93 0.069 2800 1600 130050 223 133 106 0.095 2300 1400 1100100 269 160 128 0.144 1800 1100 800200 325 194 154 0.220 1400 800 700300 362 216 172 0.282 1200 700 600500 416 248 198 0.386 1000 600 500
Optimum display luminance,
white luminance (cd/m2)Required luminance contrast
Screenillumiance
(lx)
↓
Geometric mean of ALLvalues for 20 viewers age 20–
29 at a 20° viewing angle
Optimum display luminance /Black level luminance required
to prevent floating blacks
Image ALL (%) Geometric meanfor 21 viewers
age 20-29
Image ALL (%)
Ergonomic Design Guidelines for Flat Panel Display Televisions
Japan Ergonomics Society 15
8. White point (color temperature)
(1) Preferred color temperature
The color temperature at a preferred white point depends on the color temperature of
environmental illumination, image content, screen visual angle, and display luminance30)–32).
Of these, the color temperature of environmental illumination has the largest effect. Figure
15 shows a distribution of relative color temperatures for incident ambient light of daytime
and nighttime television screens in the living rooms of 83 households. The nighttime
distribution is divided into two, to distinguish between the significant differences in color
temperatures between filament-based or colored fluorescent light bulbs and 4000 K and
higher white fluorescent or daylight fluorescent bulbs. Because daytime lighting includes
the effects of external light, the 4000–4500 K optimum range covers a wide distribution.
Preferred color temperature settings under such lighting conditions are needed.
Figure 15. Distribution of color temperatures for room lighting in household living rooms. Measurements were made in 83 households, some during both daytime and nighttime.
Figure 16 shows the preferred color temperature for the white point when displaying
several images under room illumination color temperatures30). These results were obtained
from experiments with 20 student participants, under conditions of 100 lx screen
illuminance and 150 cd/m2 white luminance as the display luminance. Preferred
conditions were roughly 5500–6500 K when environmental illumination was incandescent
lighting, 7000–9000 K under white fluorescent lighting, and 7500–10,000 K under daylight
fluorescent lighting. Higher color temperatures were desired for natural scenes than for text
screens, but on average color temperature should be set at roughly 3000 K higher than the
color temperature of the room lighting.
0
5
10
15
20
25
30
35
~20
00
~25
00
~30
00
~35
00
~40
00
~45
00
~50
00
~55
00
~60
00
~65
00
%
Color temperature (K) of room lighting
Daytime N=78Nighttime N=31
Ergonomic Design Guidelines for Flat Panel Display Televisions
16
Preferred color temperature is also affected by the apparent screen size, that is, by the
screen visual angle. As Figure 17 shows, when the visual angle is small, in other words
when the viewing distance is long, higher color temperatures are preferred. Figures 18 and
19 show that there is also a relationship between display luminance and ambient
illuminance and that higher color temperature is preferred for higher display luminance and
lower ambient luminance. This is likely because viewers prefer higher color temperature
images when the screen appears to be relatively brighter.
Figure 16. Illumination color temperatures and television screen preferred color temperatures. Data are the mean with ±1 standard deviation of 20 college students. Images used: “Fruit basket”, Standard Image JIS XYZ/SCID, sRGB, JIS X9204:2000 compliant; and “Woman and glass”, Standard Image JIS XYZ/SCID, sRGB, JIS X9204:2000 compliant.
90
100
110
120
130
140
150
160
170
180
190
200150200250300350
Inve
rse
colo
r te
mpe
ratu
re (m
ired
)
Pre
ferr
ed c
olor
tem
pera
ture
(K)
Illumination color temperature (mired)
White screenText screenFruit basketWoman and glass
5000
6000
7000
8000
9000
10000
11000
2950K 4600K 5800K
Ergonomic Design Guidelines for Flat Panel Display Televisions
Japan Ergonomics Society 17
Figure 17. Television screen preferred color temperature and screen visual angle (viewing distance). Data are the mean with ±1 standard deviation for 20 college students.
Figure 18. White point preferred color temperature by display luminance and screen illuminance. Image used is “Woman and glass” JIS XYZ/SCID. Data are the mean with standard deviation for 20 college students.
90
100
110
120
130
140
150
160
170
180
190
200150200250300350
Inve
rse
colo
r te
mpe
ratu
re (
mir
ed)
Pre
ferr
ed c
olor
tem
pera
ture
(K
)
Illumination color temperature (mired)
"Woman and glass" and "Fruit basket" average
48°(2H)17°(6H)
5000
6000
7000
8000
9000
10000
11000
2950K 4600K 5800K
Viewing angle
8090100110120130140150160170180190200210
30cd/㎡ 150cd/㎡ 30cd/㎡ 150cd/㎡
Inve
rse
colo
r te
mpe
ratu
re (m
ired
)
Pre
ferr
ed c
olor
tem
pera
ture
(K)
Display luminance (cd/㎡)
"Woman and glass" JIS XYZ/SCID30lx 300lx
5000
6000
7000
8000
9000
100001100012000
5800K
Illumination temperature
Screen illuminance
2950K
Ergonomic Design Guidelines for Flat Panel Display Televisions
18
Figure 19. White point preferred color temperature by display luminance and screen illuminance. Image used is “Fruit basket” JIS XYZ/SCID. Data are the mean with standard deviation for 20 college students.
(2) Effects of aging
Aging also affects preferred color temperature33), 34). The change is not a simple shift in
color temperature preference that advances with age, however; preferences shift according
to the degree of yellowing of the field of vision (due to cataract formation). Figure 20
shows the results of two contrasting experiments with 20 elderly participants aged 63–79
(average age 71, artificial lens recipients not included)33). In the first experiment, an image
with fixed color temperature was displayed and the preferred display luminance determined
using the adjustment method. In the second experiment, paired displays were used to
display images at 5000 K, 6500 K, and 9300 K and the same luminance, and Scheffe’s
pairwise comparison test was used to evaluate preferences. Figure 20 shows, for each
participant, the obtained preferred display luminance values on the horizontal axis, and the
results of the color temperature evaluation test on the vertical axis.
Participants who preferred high luminance also preferred relatively high color
temperatures, and those who preferred low luminance tended to prefer low color
temperatures. No such trend was seen in similar testing on young participants. This
suggests that older participants who preferred high luminance have experienced advanced
field of vision yellowing (cataract development), and that this yellowing results in a
preference for higher color temperatures. In the future, when designing and developing
television screens, display engineers will increasingly need to take into consideration such
individual differences in the effects of aging.
8090100110120130140150160170180190200210
30cd/㎡ 150cd/㎡ 30cd/㎡ 150cd/㎡
Inve
rse
colo
r te
mpe
ratu
re (m
ired
)
Pre
ferr
ed c
olor
tem
pera
ture
(K)
Display luminance (cd/㎡)
"Fruit basket" JIS XYZ/SCID30lx 300lx
5000
6000
7000
8000
9000
100001100012000
Screen illuminance
2950K 5800K
Illumination temperature
Ergonomic Design Guidelines for Flat Panel Display Televisions
Japan Ergonomics Society 19
Figure 20. Test results for preferred display luminance at fixed color temperature (horizontal axis) and paired comparison testing for preference using displays with varying color temperature (vertical axis). Results are from a combination of two tests with 20 participants, aged 63–79 (mean age 71).
9. Viewing distance
The standard viewing distance for an HDTV set is 3H (three times the height of the
screen), the distance at which individual pixels are no longer visible to a viewer with
normal vision. This standard viewing distance, however, is not necessarily the same as the
viewer’s preferred viewing distance, which comes from the distance at which a feeling of
presence occurs and scan lines are not discernable when viewing a static image1)–6). When
determining the viewing distance for televisions in general residences, the preferred
viewing distance should be used as the optimum viewing distance21), as viewing television
from within an appropriate range is necessary for reducing visual discomfort9). The
optimum viewing distance is influenced by both the television’s screen size and display
luminance16), 17), 21), 35)–37), but screen size is the dominant factor21), 35)–37).
Figures 21 and 22 show the optimum viewing distance and minimum acceptable viewing
distance for various screen sizes21). Figure 21 shows viewing distances in actual dimensions,
while Figure 22 shows viewing distances as a multiple of screen height (H). Note that
given screen sizes are in the range 24–65 in., and display luminance is assumed to be 200
-1.5
-1
-0.5
0
0.5
1
1.5
0 100 200 300 400 500 600 700
Com
para
tive
tes
t re
sult
s fo
r pr
efer
red
colo
r te
mpe
ratu
re; S
hef
fe's
pai
rwis
e co
mpa
riso
n s
core
Results of separate testing for preferred display luminance (cd/㎡)
5000K
9300K
6500K
White point○9300K rating R2=0.43
●5000K rating R2=0.48
Pre
ferr
ed→
←D
isli
ke
Individual participant data set
Ergonomic Design Guidelines for Flat Panel Display Televisions
20
cd/m2. Mean values and ±1 standard deviations are given for each case. Table 4 gives the
information in Figures 21 and 22 as actual values. Before selecting a screen size, viewers
should consider the available space in the room in which the television will be placed to
ensure that a sufficient viewing distance is available.
Figure 23 shows actual viewing distances for households with flat panel televisions.
Almost no homes with relatively large screens had sufficient space for viewing from a 3H
distance. Also of note is that in many homes, viewing occurs from beyond the optimum
distance.
Figure 21. Optimum viewing distance (cm) and minimum acceptable viewing distance (cm) for various screen sizes. Means and ±1 standard deviations (SD) for 27 participants are given for each case.
0
50
100
150
200
250
300
350
400
20 30 40 50 60 70
DA
: Vie
win
g di
stan
ce (c
m)
S: Diagonal screen size (in.)
DAPreferred=3.41S +93
DAClosest=1.81S +50
Optimum viewing distance
Minimum acceptable viewing distance
+1SD
-1SD
+1SD
-1SD
Ergonomic Design Guidelines for Flat Panel Display Televisions
Japan Ergonomics Society 21
Figure 22. Optimum viewing distance (H: multiple of screen height) and minimum acceptable viewing distance (H) for various screen sizes. Means and ±1 standard deviations (SD) for 27 participants are given for each case.
Table 4. Optimum viewing distance and minimum acceptable viewing distance. Means and ±1 standard deviations (SD) are given for optimum viewing distance. Approximately 68% of participants fall within ±1 SD.
0
1
2
3
4
5
6
7
8
20 30 40 50 60 70
DH
:Rel
ativ
evi
ewin
g di
stan
ce (
H)
S: Diagonal screen size (in.)
+1SD
-1SD
+1SD
-1SD
Optimum viewing distance
Minimum acceptable viewing distance
cm H cm H-1SD Mean +1SD -1SD Mean +1SD Mean Mean
24 138 175 212 4.60 5.85 7.09 93.4 3.13
26 143 182 220 4.41 5.61 6.81 97.1 3.00
32 158 202 246 3.97 5.07 6.17 107.9 2.71
37 171 219 267 3.71 4.75 5.80 117.0 2.54
40 179 229 280 3.59 4.60 5.62 122.4 2.46
42 184 236 288 3.52 4.51 5.51 126.0 2.41
46 194 250 305 3.39 4.36 5.33 133.3 2.33
50 205 264 322 3.28 4.23 5.18 140.5 2.26
52 210 270 331 3.24 4.17 5.11 144.1 2.22
55 217 281 344 3.17 4.09 5.02 149.6 2.18
58 225 291 356 3.12 4.02 4.93 155.0 2.14
60 230 298 365 3.08 3.98 4.88 158.6 2.12
65 243 315 386 3.00 3.89 4.77 167.7 2.07
Optimum viewing distanceDiagonalscreen size
(in.)
Minimumacceptable viewing
distance
Ergonomic Design Guidelines for Flat Panel Display Televisions
22
Figure 23. Screen size and viewing distance (H) for homes with flat panel televisions. Values are for 16:9 aspect ratio LCD and plasma televisions only (CRT-based televisions are excluded). The graph shows experimentally determined values for both optimum viewing distance and minimum acceptable viewing distance.
10. Display height
General guidelines for the optimum height for a television screen differ from those for
computer monitors. The best height for a computer monitor is generally taken to be such
that the top edge of the monitor is at the same height as the eyes, or slightly lower38), but
television heights should be such that the viewer’s eyes are at an equal height to the center
of the screen38) (see Figure 24). This guideline does not vary with screen size or viewing
distance, a finding that has been verified through both experiments and field surveys39).
Figure 25 shows the results of preferred screen height adjustments for viewing 32-, 42-,
and 65-in. televisions while sitting in chairs and on the floor. Eye height was approximately
110 cm above the floor in the former case, and 80 cm in the latter, so preferred height was
equivalent to one in which eye level was even with the middle of the screen. Figure 26
shows eye height while viewing television for 393 persons in 83 households. Setting aside
the case of viewing from a reclined position, televisions should be placed in accordance
with these heights.
Figure 27 shows the line of sight angle for these 393 persons while looking at the center
of the screen. The distribution has a mode of 0° horizontal, indicating that positioning so
that the center of the screen is at eye level is the most common real-world case.
Figure 28 shows a graph of screen size and screen center height for 83 households.
Screen center height was roughly 60–100 cm, and was not dependent on screen size.
0
2
4
6
8
10
12
14
16
18
15 20 25 30 35 40 45 50 55
Vie
win
g di
stan
ce (H
)
Diagonal screen size(in.)
LCD (32 households, N=149)
PDP (10 households, N=41)
Standard viewing distance: 3H
Optimum viewing distance
Minimum acceptable viewing distance
Ergonomic Design Guidelines for Flat Panel Display Televisions
Japan Ergonomics Society 23
Figure 24. Optimum television screen height.
Figure 25. Optimum television screen height (from floor to screen center). Mean and ±1 standard deviations for 31 participants.
Figure 26. Actual eye height (distance from floor to eyes) while viewing television.
50
60
70
80
90
100
110
120
130
150 250 400
Opt
imu
m s
cree
n h
eigh
t (c
m)
0150 250 400
32 in. 42 in. 65 in.
Sitting on chair Sitting on floor
Viewing distance (cm)
Average eye height
sitting on chair
Average eye height
sitting on floor
0
10
20
30
40
50
10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100
105
110
115
120
125
130
135
Fre
quen
cy
Viewer eye height (cm)
Sprawl on floorSitting on floorSitting in chair
N=393
Screen height should be such that the line of sight is horizontal when viewing the screen center
Ergonomic Design Guidelines for Flat Panel Display Televisions
24
Figure 27. Line of sight angle to screen center.
Figure 28. Television screen center height for 83 households.
11. Screen tilt angle
(1) Optimum tilt angle
We take optimum tilt angle as the most preferred vertical surface angle as determined by
test participants when given a device allowing them to freely change the screen tilt angle
while viewing television. Defined this way, tilting the screen so that a line drawn from the
viewer’s eyes the television screen center is normal to the screen does not necessarily result
in the optimum tilt angle. The actual optimum tilt angle varies with the relationship
between eye and screen height, as shown in Figure 29. When these heights are equal, an
approximately 1.5° forward tilt was the optimum tilt angle. When the screen center height
is 30 cm lower than eye height, at a 3H viewing distance the predicted optimum angle
based on a screen-normal line is an 8° backward tilt, but the optimum tilt angle is actually
40
60
80
100
120
140
160
15 20 25 30 35 40 45 50 55
Scr
een
cen
ter
hei
ght
(cm
)
Screen size (diagonal in.)
CRT N=41 LCD N=32 PDP N=10
0
20
40
60
80
100
-24
-22
-20
-18
-16
-14
-12
-10 -8
-6
-4
-2 0 2 4 6 8
10
12
14
16
18
20
22
24
Fre
quen
cy
Line of sight angle to center of screen (deg)
Sprawl on floorSitting on floorSitting in chair N=393
Mean -1.06°
UpDown
Ergonomic Design Guidelines for Flat Panel Display Televisions
Japan Ergonomics Society 25
an approximately 2° backward tilt. Conversely, when the screen center height is 30 cm
above eye height, at a 3H viewing distance the predicted optimum angle based on a
screen-normal line is an 8° forward tilt, but the optimum tilt angle is actually an
approximately 4° forward tilt (see Figure 30). These values are based on viewing a 58-in.
plasma television from a 3H viewing distance, but roughly the same values were obtained
from a 5H viewing distance, indicating that within a 3–5H viewing distance range there is
little influence of viewing distance on optimum tilt angle. Equation (4) gives the
relationship between optimum screen tilt angle and screen center height for a 3–5H viewing
distance:
Θ = 0.10 h + 1.58 (4)
where the screen optimum tilt angle θ (deg) is positive for a forward tilt, and negative for a
backwards tilt, h (cm) is the relative screen center height with eye height taken as 0, and
–40 ≤ h ≤ 40.
Figure 29. Optimum tilt angle of TV screen as a function of screen center height.
Data from 25 participants.
-12
-10
-8
-6
-4
-2
0
2
4
6
8
10
12
-40 -30 -20 -10 0 10 20 30 40
θ:O
ptim
um
til
t an
gle
(deg
)
h: Screen center height relative to eye height (cm)
80cm110cm
140cm
Screen center height
Below eye height← |→Above eye height
Bac
kw
ard
←|→
For
war
d
θ=0.10h+1.58
Angle of line connectingscreen center and eyes
0°+-
ForwardBackward
+
-
Scr
een
Cen
ter
Hei
ght 3H~5H
Backrest angle is 105 deg
Experimental Setting
θ
Scr
een
cen
ter
hei
ght
Experimental setting
Ergonomic Design Guidelines for Flat Panel Display Televisions
26
Figure 30. Screen height and screen optimum tilt angle.
(2) Minimize screen glare by tilting screen
For large-screen televisions, changing the screen tilt is a common way to avoid glare
from reflected lighting fixtures. Figure 31 shows a distribution of lighting fixture
reflections on television screens, based on a television viewing environment survey of 83
households40). The figure uses the relationship between television screen placement,
lighting fixture placement, and viewer eye position to show where lighting fixtures would
be reflected, causing glare, if screen size were increased. Plots assume a vertical screen
surface.
Figure 32 shows the probability that lighting fixtures will be reflected on various sizes
of television screens, based on the results of Figure 31. In other words, the figure shows the
probability that lighting fixtures will be reflected in field living rooms when the display
height is changed for different screen sizes. As the screen size or height increases, the
probability that lighting fixtures will be reflected also increases. Even for a 50-in. television,
if the height of the screen’s lower edge is 70 cm, lighting fixtures will be reflected, causing
glare, in close to 10% of households.
Figure 33 shows lighting fixture reflection angle distributions, divided into vertical and
horizontal directional components. Taking the vertical components, most reflections are in
the range 8–15° normal to the screen surface, indicating that reflection avoidance can be
realized with a relatively shallow cutoff angle for lighting fixture shielding.
Tilting the screen forward can also lower the probability of light fixture reflection.
Figure 34 shows the effects of reflection reduction through forward screen tilting, and
indicates that a forward tilt of 5° reduces the probability of lighting fixture reflection by
Preferred tilt angle is not thesame as the angle at whichline of sight is normal toscreen. Preferred tilt angle isthe same at 3H and 5H,indicating no relation in the3H-5H range.
Angle at which line of sight is
normal to screen from 3H
Preferred tilt angle
3H 5H30cm
30cm
+4° +8°
+1.5°
0°
- 2° - 8°
Ergonomic Design Guidelines for Flat Panel Display Televisions
Japan Ergonomics Society 27
roughly half. The remaining problem is to what extent the screen can be tilted before
interfering with image viewing. Figure 35 shows extents to which viewers find screen tilt
annoying, and indicates that when screen height is at eye level a screen tilt of up to around
5° is permissible. Forward screen tilting within this range is therefore a useful method for
avoiding lighting fixture reflection.
Figure 31. Distribution of lighting fixture reflections, overlaid with various television screen sizes with bottom edge 60 cm above floor.
Figure 32. Probability of lighting fixture reflection by screen size and height for living rooms of 83 households.
0
50
100
150
200
250
300
-350 -300 -250 -200 -150 -100 -50 0 50 100 150 200 250 300 350
Hei
ght
from
flo
or (
cm)
Distance from screen center (cm)
For screen bottom edge 60 cm above floor
42 in.2%
150 in.92%
65 in.15%
100 in.67%
52 in.5%
83 households (n=1015)
0
10
20
30
40
50
60
70
80
30 40 50 60 70 80 90 100
Pro
babi
lity
of r
efle
ctio
n (%
)
Diagonal screen size (in.)
0 cm35 cm50 cm70 cm
Height of bottom edge
Ergonomic Design Guidelines for Flat Panel Display Televisions
28
Figure 33. Distribution of illumination fixture reflections on television screens in 83 households.
Figure 34. Reduction of illumination fixture reflection through tilting the screen forward. Bottom edge of screen is assumed to be 60 cm above floor.
0 5 10 15
-10-6-226
10141822263034384246
Frequency (%)
Inci
den
ce a
ngl
e of
ref
lect
ion
, ve
rtic
al c
ompo
nen
t (de
g)
83 householdsN=1015
+
‐ 0
5
10
15
-60
-50
-40
-30
-20
-10 0 10 20 30 40 50 60
Fre
quen
cy (
%)
Incidence angle of reflection, horizontal component (deg)
83 householdsN=1015
+‐
0
5
10
15
20
25
30
35
40
0 1 2 3 4 5 6 7 8 9 10
Pro
babi
lity
of r
efle
ctio
n (%
)
Screen tilt angle (deg)
4050607080
Diagonal screen size (in.)
+
-
Top view
+
-
Side view
Ergonomic Design Guidelines for Flat Panel Display Televisions
Japan Ergonomics Society 29
Graphs are results for television viewing in the four situations shown below:
Figure 35. Relationship between screen tilt angle and degree of annoyance. Mean and ±1 standard deviation for 24 viewers at a 3H viewing distance.
110cm
3H
3H
①
Side view Top view
140cm
3H
3H
②
Side view Top view
110cm
3H③
30°
Side view Top view
④
30°
Top view
140cm
3H
Side view
0
1
2
3
4
5
6
0 2.5 5 7.5 10 12.5 15 17.5
Mea
n R
atin
g
Screen tilt angle (deg)
Front / 110cm height
Front / 140cm height
Right / 110cm height
Right / 140cm height
Viewing comfort rating for tilted screen
Imperceptible
Acceptable limit
Slightly annoying
Annoying
Very annoying
①
②
③
④
↓ See figure below
Ergonomic Design Guidelines for Flat Panel Display Televisions
30
12. Viewing angle
No display can avoid the differences in display characteristics such as display
luminance, contrast, and chromaticity that arise from varying the viewing angle. Under
actual viewing conditions, however, such differences are not a problem as long as such
changes are less than perceptible limits, or at least within acceptable limits. It is therefore
necessary to establish what range of viewing angles allows for television viewing in actual
homes. Restricting changes in display characteristics in that range to within acceptable
levels will thus be a goal for ergonomic design and development.
Figure 36. Viewing positions for 393 locations in 83 households.
Figure 36 shows a graph of eye positions with respect to television screen centers
during television viewing from 393 locations in 83 household living rooms. Data were
obtained during a survey conducted between 2007 and 20088), 19). No significant difference
according to display technology or screen size was indicated. As described above, actual
viewing positions are largely determined by furniture placement and room size.
Figure 37 shows a distribution of the absolute value of viewing angles normal to screen
center, split into horizontal and vertical components, for which 95th percentile values are
40° horizontal and 10° vertical. Results obtained in television viewing position surveys
conducted in 200422) and 200525) are roughly the same as these values, despite different
ratios of screen size and display technology between those years. These results also agree
with experimental tests performed to find tolerable horizontal viewing angle ranges for
LCD screens41). Therefore, to satisfy 95% of viewers in terms of viewing angle
characteristics, such changes must be held to within imperceptible or tolerable ranges for
0
200
400
600
200
400
600
-90° -75°-60°
-45°
-30°
-15°
0°
15°
30°
45°
60°
75°90°
CRT N=203
LCD N=149
PDP N=41
cm
cm
cm
cm
0
200
400
600
200
400
600
-30°
-20°
-10°
0°
10°
20°
30°
Top view
Screen center
Side view
83 households, N=393 No significant difference in viewing range by display
Ergonomic Design Guidelines for Flat Panel Display Televisions
Japan Ergonomics Society 31
viewing angles of ±40° horizontally, and ±10° vertically. Note, however, that the discussion
so far extends only to viewing domains based on the screen center, but, as shown by Figure
38 and Equation (5) therein, the viewing angle in actual television viewing is greatest for
far side edges, so screen size must also be taken into consideration42).
Figure 37: Viewing angle distributions, normal to screen center. Left: horizontal direction. Right: Vertical direction.
Figure 38. Difference in viewing angles for screen center and screen edge.
Figures 39 and 40 respectively show distributions of viewing angles for screen far side
edges (farthest points) of 32-in. and 55-in. screens, divided into horizontal and vertical
direction components. For the 32-in. screen horizontal angle (Figure 39, left) the 95th
percentile value is 46°, and that for the 55-in. screen (Figure 40, left) is 50°, both of course
larger than the screen center value of 40°. The vertical values are 17° for the 32-in. screen
(Figure 39, right) and 21° for the 55-in. screen (Figure 40, right). It is therefore necessary
0
10
20
30
40
50
60
70
80
90
100
0
5
10
15
20
25
30
35
40
0 6 12 18 24 30 36 42 48 54 60
Cu
mu
lati
ve fr
equ
ency
(%
)
Fre
quen
cy
Horizontal viewing angle from screen center (deg)
83householdsN=393
95 %
ile
90 %
ile
75 %
ile
0
10
20
30
40
50
60
70
80
90
100
0
20
40
60
80
100
120
0 2 4 6 8 10 12 14 16 18 20 22 24
Cu
mu
lati
ve fr
equ
ency
(%
)
Fre
quen
cy
Horizontal viewing angle from screen center (deg)
95 %
ile
90 %
ile
75 %
ile
83householdsN=393
Vertical direction Horizontal direction
VD
D
θ
Viewing angle with respect to the far edge of the screen
α
θ: Viewing angle with
respect to the far edge of
the screen (deg)
VD: Viewing distance (cm)
α : Viewing angle to the
center of the screen (deg)
D : Distance from screen
center to the edge (cm)
Ergonomic Design Guidelines for Flat Panel Display Televisions
32
to design screens, LCDs in particular, so that changes in display characteristics within these
ranges are within imperceptible or at least tolerable levels.
Table 5 shows 95th percentile, 90th percentile, 3rd quartile, and 75th percentile values
for a variety of screen sizes from 24 to 65 in. for analyses similar to those of Figures 39 and
40. Keeping image display changes to an imperceptible level for the given ranges will
result in the applicable percentage of viewers viewing the television without noticing any
change in display characteristics due to viewing angle. As these results indicate, it is
necessary to sufficiently take screen size into account when designing viewing angle
characteristics.
Figure 39. Viewing angles for farthest point on a 32-in. screen. Left: horizontal direction. Right: vertical direction.
Figure 40. Viewing angles for farthest point on a 55-in. screen. Left: horizontal direction. Right: vertical direction.
010
2030
405060
7080
90100
0
5
10
15
20
25
30
35
2 8 14 20 26 32 38 44 50 56 62
Cu
mu
lati
ve fr
equ
ency
(%
)
Fre
quen
cy
Horizontal viewing angle for farthest point on screen (deg)
83 householdsN=393
90 %
ile
95 %
ile
75 %
ile
0102030405060708090100
0102030405060708090
100
2 6 10 14 18 22 26 30 34
Cu
mu
lati
ve fr
equ
ency
(%
)
Fre
quen
cy
Vertical viewing angle for farthest point on screen (deg)
95 %
ile
90 %
ile
75 %
ile
83 householdsN=393
32 in., Horizontal direction 32 in., Vertical direction
55 in., Horizontal direction 55 in., Vertical direction
0102030405060708090100
0
5
10
15
20
25
30
35
2 8 14 20 26 32 38 44 50 56 62
Cu
mu
lati
ve fr
equ
ency
(%)
Fre
quen
cy
Horizontal viewing angle for farthest point on screen (deg)
83 householdsN=393
90 %
ile
95 %
ile
75 %
ile
0102030405060708090100
0
10
20
30
40
50
60
70
80
2 6 10 14 18 22 26 30 34
Cu
mu
lati
ve fr
equ
ency
(%)
Fre
quen
cy
Vertical viewing angle for farthest point on screen (deg)
83 householdsN=393
90 %
ile
95 %
ile
75 %
ile
Ergonomic Design Guidelines for Flat Panel Display Televisions
Japan Ergonomics Society 33
Table 5. Actual television viewing angles for screen center and farthest screen point at various screen sizes, with percentile values.
13. Conclusions
These Guidelines use real-world viewing of flat panel display televisions and
multifaceted laboratory testing to summarize principles that should be taken into
consideration in the ergonomic design and development of televisions that can most
comfortably be viewed under real-world environments and usage conditions. These
Guidelines were created with the goal of allowing engineers involved in many aspects of
television technology to incorporate such factors into their designs as viewing environment
and conditions, individual differences due to age and other causes, and differences in
displayed images. Please note that the optimum values given for the various design factors
discussed here are optimal developmental goals strictly from the standpoint of ergonomics,
and should be pursued only to the extent possible within the scope of other product
development constraints.
Developing new displays that better suit the display characteristics for a wide variety of
viewers and viewing conditions will result in more comfortable viewing, while consuming
less energy. To that end, we hope that these Guidelines will be useful to a wide variety of
television engineers.
24 32 42 55 65
Horizontal 40 45 46 48 50 52
Vertical 10 15 17 19 21 24
Horizontal 35 40 42 44 46 48
Vertical 7 13 14 16 19 21
Horizontal 25 32 33 35 38 40
Vertical 5 9 11 13 15 17
Unit:deg
75th
Viewing anglewith respect
to screencenter
Diagonal screen size (in.)Percentile Direction
Viewing angle with respect to screen's farthestpoint at various sizes
95th
90th
Ergonomic Design Guidelines for Flat Panel Display Televisions
34
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Ergonomic Design Guidelines for Flat Panel Display Televisions
38
Annex
Results of Web questionnaire survey on viewing conditions of
LCD televisions at home
‐ A comparison of six countries ‐
(Brazil, China, India, Japan, the United Kingdom, and the United States)
Country Survey period Number of samples
2011/7/20-7/21 2,060
2011/7/13-7/27 1,000
2009/7/28-8/16 580
Results of Web questionnaire survey on viewing conditions of LCD televisions at home
- A comparison of six countries -
( Brazil , China , India , Japan ,the United Kingdom , the United States )
Gender and age
Male
20s 206 120 115 100 58 58
30s 206 120 115 100 58 58
40s 206 104 107 100 58 58
50s 206 109 109 100 58 5860s
or more 206 47 54 100 58 58
Sub total 1030 500 500 500 290 290
Fem
ale
20s 206 130 162 100 58 58
30s 206 130 162 100 58 58
40s 206 115 130 100 58 58
50s 206 104 40 100 58 5860s
or more 206 21 6 100 58 58
Sub total 1030 500 500 500 290 290
Total 2060 1000 1000 1000 580 580
The number of samples for each category
Japan China India BrazilThe United Kingdom
The United States
39
No. Question
Q1 How many televisions do you have in your home?
Q2 Which direction(s) do the windows face?
Q3 Do you adjust the lighting when watching television?
Q4 When did you purchase the LCD television that you mainly watch in the living room with your family and such?
Q5 Have you ever made any picture quality adjustments (brightness, color, etc) on the LCD television that you mainly watch in the living room with your family and such?
Q6 What is the screen size of the LCD television that you mainly watch in the living room with your family and such?
Q7 What size television would you like to put in your living room, etc. in the future to mainly use with your family and such?
Q8 What size television could you actually fit in the room (e.g. living room) where you would put the television to be mainly watched with your family and such?
Q9 On average, how many hours a day do you spend watching television?
Q10What is the number of people at your home who watch the television that you mainly watch in the living room with your family and such? *Please include yourself in the number. *Answer with the most frequent number of people watching television together.
Q11 What kinds of programming do you frequently watch on the television that you mainly watch in the living room with your family and such. Choose up to three.
Q12 This question concerns the LCD television that you mainly watch in the living room with your family and such. Do you use the television for anything else other than watching television?
Q13 This question concerns the television that you mainly use at home LCD. For each statement below, choose one response that best applies to you.
Q14 Which of the following features do you think are necessary?
18.1%
231.4%
333.8%
415.9%
57.9%
6 or more2.9%
(n=1000)
19.0%
229.0%
326.4%
422.6%
57.8%
6 or more5.3%
(n=580)
116.9%
234.0% 3
25.9%
416.6%
54.0%
6 or more2.8%
(n=580)
131.4%
250.5%
314.6%
42.6%
50.5%
6 or more0.4%
(n=1000)
120.1%
251.6%
323.2%
44.2%
50.5%
6 or more0.4%
(n=1000)
134.8%
230.4%
319.6%
410.1%
53.3%
6 or more1.7%
(n=2060)
Q1:How many televisions do you have in your home?
Avg:2.2 televisions Avg:2.1 televisions Avg:2.7 televisions
Avg:1.9 televisions Avg:2.9 televisions Avg:3.1 televisions40
0%
10%
20%
30%
40%
50%
North
East
South
West
インド (n=1000)
ブラジル(n=1000)
中国 (n=1000)
日本 (n=2060)
イギリス (n=580)
アメリカ (n=580)
Q2:Which direction(s) do the windows face?
I don't adjust
the lighting57.9%
I turn down the
lights21.4%
I turn off the lights14.3%
Others6.4%
(n=580)
Q3:Do you adjust the lighting when watching television?
I don't adjust
the lighting90.3%
I turn down the
lights8.1%
I turn off the lights1.2% Others
0.5%
(n=2060)
I don‘t adjust
the lighting63.5%
I turn down the
lights24.5%
I turn off the lights6.9%
Others5.1%
(n=1000)
I don't adjust
the lighting77.7%
I turn down the
lights16.7%
I turn off the lights5.4%
Others0.2%
(n=1000)
I don't adjust
the lighting56.6%
I turn down the
lights27.6%
I turn off the lights10.3%
Others5.5%
(n=580)
I don‘t adjust
the lighting60.6%
I turn down the
lights22.7%
I turn off the lights14.9%
Others1.8%
(n=1000)
41
Within last year
19.9%
Within last 2 years43.5%
Within last 3 years23.1%
Within last 5 years11.2%
Within last 10 years1.5%
More than 10 years ago
0.4%
Don‘t know0.4%
(n=1000)
Within last year
34.7%
Within last 2 years22.1%
Within last 3 years18.3%
Within last 5 years15.0%
Within last 10 years6.0%
More than 10 years ago
0.3%
Don't know3.6%
(n=2060)Avg:1.9 years agoAvg:2.1 years ago
Within last year
39.1%
Within last 2 years29.1%
Within last 3 years14.8%
Within last 5 years10.5%
Within last 10 years3.3%
More than 10 years ago
1.7%
Don't know1.4%
(n=580)
Within last year
35.3%
Within last 2 years37.2%
Within last 3 years16.0%
Within last 5 years7.9%
Within last 10 years1.7%
More than 10 years ago
0.5%
Don't know1.2%
(n=580)
Within last year
34.2%
Within last 2 years33.9%
Within last 3 years20.6%
Within last 5 years8.4%
Within last 10 years1.9%
More than 10 years ago
0.6%
Don‘t know0.4%
(n=1000)
Within last year
45.9%Within last 2 years34.6%
Within last 3 years12.8%
Within last 5 years5.1%
Within last 10 years0.9%
More than 10 years ago
0.3%
Don‘t know0.4%
(n=1000)
Q4:When did you purchase the LCD television that you mainly watch in the living roomwith your family and such?
Avg:1.7 years ago
Avg:1.4 years ago Avg:1.7 years ago Avg:1.9 years ago
Yes39.5%
No60.5%
(n=580)
Yes61.2%
No38.8%
(n=1000)
Yes64.6%
No35.4%
(n=1000)
Yes56.3%
No43.7%
(n=1000)
Q5: Have you ever made any picture quality adjustments (brightness, colour, etc) on the LCD television that you mainly watch in the living room with your family and such?
Yes43.8%
No56.2%
(n=2060)
Yes43.1%
No56.9%
(n=580)
42
0%
10%
20%
30%
40%
50%
19 in. or
smaller
20-24 in.
25-29 in.
30-34 in.
35-39 in.
40-44 in.
45-49 in.
50-59 in.
60 in. or
larger
インド
(n=1000)
ブラジル
(n=1000)
中国
(n=1000)
日本
(n=2060)
イギリス
(n=580)
アメリカ
(n=580)
Q6:What is the screen size of the LCD television that you mainly watch in the living room with your family and such?
31.3 in.
Average
36.2 in. 38.3 in. 35.3 in. 34.0 in. 39.8 in.
0%
10%
20%
30%
40%
50%19 in
. or sm
aller
20-24 in.
25-29 in.
30-34 in.
35-39 in.
40-44 in.
45-49 in.
50-59 in.
60 in. or
larger
インド
(n=1000)
ブラジル
(n=1000)
中国
(n=1000)
日本
(n=2060)
イギリス
(n=580)
アメリカ
(n=580)
Q7:What size television would you like to put in your living room, etc. in the future to mainly use with your family and such?
31.2 in.
Average
37.0 in. 39.4 in. 35.8 in. 33.9 in. 40.1 in.
43
0%
10%
20%
30%
40%
50%
19 in. or
smaller
20-24 in.
25-29 in.
30-34 in.
35-39 in.
40-44 in.
45-49 in.
50-59 in.
60 in. or
larger
インド
(n=1000)
ブラジル
(n=1000)
中国
(n=1000)
日本
(n=2060)
イギリス
(n=580)
アメリカ
(n=580)
Q8:What size television could you actually fit in the room (e.g. living room) where you would put the television to be mainly watched with your family and such?
35.4inch
平均
41.7inch 40.6inch 41.0inch 45.2inch 51.4inch35.4 in.
Average
41.7 in. 40.6 in. 41.0 in. 45.2 in. 51.4 in.
0
10
20
30
40
50
インド ブラジ 中国 日本 英国 米国
31.3 36.2 38.3
35.3 34.0 39.8 31.2
37.0 39.4 35.8 33.9
40.1 35.4
41.7 40.6 41.0 45.2
51.4 Owned screen size
Wanting screen size
Can be set up screen size
① Owned screen size
② Wanting screen size
③ Can beset up
screen size② - ① ③ - ① ③ - ②
31.3 31.2 35.4 -0.1 4.2 4.2
36.2 37.0 41.7 0.8 5.5 4.7
38.3 39.4 40.6 1.1 2.2 1.2
35.3 35.8 41.0 0.5 5.7 5.2
34.0 33.9 45.2 -0.1 11.2 11.3
39.8 40.1 51.4 0.3 11.6 11.3 (Unit : in.)
in.
Average
44
Q9:On average, how many hours a day do you spend watching television?
Mean
Category3.6 3.2 3.4 4.1 4.2 4.7
Gen
der
Male 3.1 3.0 3.1 3.8 4.1 4.8
Female 4.0 3.4 3.6 4.5 4.3 4.5
Age
20s 3.3 3.0 3.6 3.4 3.8 4.4
30s 3.3 3.1 3.2 4.0 3.8 4.6
40s 3.3 3.0 3.2 4.1 4.5 4.3
50sor more 3.9 3.6 3.4 4.6 4.4 5.0
(Unit : hour)
I watch it alone22.4%
I watch it with another person54.0%
I watch it with 2 others14.1%
I watch it 3 or more
others9.5%
(n=580)
I watch it alone
6.7%
I watch it with another person47.4%
I watch it with
2 others36.2%
I watch it 3 or more
others9.7%
(n=1000)
I watch it alone30.1%
I watch it with another person44.6%
I watch it with
2 others17.2%
I watch it 3 or more
others8.1%
(n=2060)
I watch it alone
6.5%
I watch it with another person30.9%
I watch it with
2 others33.1%
I watch it 3 or more
others29.5%
(n=1000)
I watch it alone13.6%
I watch it with another person46.6%
I watch it with
2 others27.1%
I watch it 3 or more
others12.7%
(n=1000)
I watch it alone24.1%
I watch it with another person47.2%
I watch it with
2 others15.0%
I watch it 3 or more
others13.6%
(n=580)
Q10:What is the number of people at your home who watch the television that you mainly watch in the living room with your family and such?※Please include yourself in the number.※Answer with the most frequent number of people watching television together.
Avg:2.1 persons Avg:2.5 persons Avg:2.2 persons
Avg:3.0 persons Avg:2.5 persons Avg:2.2 persons45
Q11: What kinds of programming do you frequently watch on the television that you mainly watch in the living room with your family and such. Choose up to three.
Order Genre Frequency(%) Genre Frequency
(%) Genre Frequency(%) Genre Frequency
(%) Genre Frequency(%) Genre Frequency
(%)
1 News 71.0 News 84.7 News 72.1 News 70.5 Movies 56.4 Movies 59.3
2 Variety 45.3 Drama 67.9 Movies 53.2 Movies 47.1 News 53.1 News 56.6
3 Drama 42.3 Movies 33.3 Music 33.5 Drama 45.6 Drama 52.6 Drama 44.8
4Informatio
n and talk show
30.7 Variety 32.9 Sports 32.0 Sports 41.3Document
ary, learning
37.8 Sports 31.2
5 Sports 25.0 Sports 32.5 Drama 24.5Informatio
n and talk show
24.6 Sports 27.4Document
ary, learning
27.2
6 Movies 24.3Informatio
n and talk show
16.4Informatio
n and talk show
19.4Document
ary, learning
19.7 Variety 15.3 Variety 15.0
7Document
ary, learning
18.6Document
ary, learning
12.7Document
ary, learning
11.7 Cartoons/animation 18.4
Information and
talk show12.1 Cartoons/
animation 14.1
8Cartoons/animation 11.8 Cartoons/
animation 6.8 Variety 11.2 Variety 15.6 Music 11.4Informatio
n and talk show
8.8
9 Music 10.1 Music 6.1 Cartoons/animation 11.1 Music 4.3 Cartoons/
animation 9.8 Music 5.5
71.6
25.3
18.2 16.3
21.9
36.5
0.6
15.2
83.0
32.3
14.9 12.4
24.9
32.2
1.1
10.0
64.5
22.4 24.3
18.4
32.3 33.3
0.5
17.4
60.3
26.5
5.1 2.9
11.4 9.2
0.7
29.9
75.2
37.9
9.0 7.6
14.5 15.9
2.1
15.3
75.9
36.2
5.7 7.1 10.2 9.1
1.4
19.1
0%
20%
40%
60%
80%
100%
Watch DVDs Games Internet Use as PCmonitor
Playbackcamcorder
footage
View imagesfrom digitalstill camera
Other Only use forviewing
television
インド
(n=1000)
ブラジル
(n=1000)
中国
(n=1000)
日本
(n=2060)
イギリス
(n=580)
アメリカ
(n=580)
Q12:This question concerns the LCD television that you mainly watch in the living room with your family and such. Do you use the television for anything else other than watching television?
46
-1.6 -1.2 -0.8 -0.4 0 0.4 0.8 1.2 1.6
The room is bright, contrast is low
The room is dim, contrast is low
Too bright
Too dark
Reflections on the screen from other light sources
The viewing angle is narrow
The motion blur bothers me
The colors seem too saturated
The colors seem to lack saturation
It hard to read stationary text
It hard to read moving text
Ghosting on the screen
Sometimes my eyes get tired
Sometimes I feel motion sick
It hard to look at other things
インド
(n=1000)
ブラジル
(n=1000)
中国
(n=1000)
日本
(n=2060)
イギリス
(n=580)
アメリカ
(n=580)
Q13:This question concerns the television that you mainly use at home LCD. For each statement below, choose one response that best applies to you.
No opinionNotice Don’t notice
Weighted average ( Definitely notice it:‐2 ~ Don’t notice it:+2 )
1 1.5 2 2.5 3
3DLED backlight
Automatic volume adjustment for commercialsAutomatic sensor ON/OFF function
Timer ON/OFF functionFull high-definition display
Built-in Blu-ray driveRecording function
Simultaneous recording of multiple programsViewing of on-demand TV shows
PC functionPlayback function
Freeze-frame functionPlayback while recording
TV phoneHigh sound quality
Multi-picture displayAutomatic picture quality control
Double-speed technologyUSB terminal(s)
HDMI terminal(s)Wireless TV tuner
Clear panel TVVoice recognition function
Built-in video gamesE-mail function
Subtitles (teletext)
インド
(n=1000)
ブラジル
(n=1000)
中国
(n=1000)
日本
(n=2060)
Q14:Which of the following features do you think are necessary?
Will use if available Must haveNot required
Weighted average ( Not required:+1 Will use if available:+2 Must have:+3 )
47