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A Research on Curved Display Comparing to Flat Display Regarding Posture, Tilt Angle, Focusing Area and Satisfaction

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Objective: This study is conducted on the differences between flat and curved displays with respect to location of focused points, posture and satisfaction as well as preferred tilt angles. Background: In order to avoid physical and eye fatigue caused by misplayed sitting posture, many studies have asserted that the display requires appropriate location, size and tilt angle as well as curvature. However, most studies have focused on the work environment and the results are varied in the extent. Method: Eye height data in sitting posture were collected from 30 participants. Participants selected the most comfortable viewing angle within the range from 0^{\circ} to 12^{\circ} while watching videos for both curved and flat display. Then, physical and eye fatigue and overall satisfaction were subjectively evaluated. Lateral diagram describing viewing display condition was set and used to develop linear models for expecting the preferred tilt angle. Results: Due to sitting in the natural viewing posture rather than upright, the eye height is lowered to about 4.6 centimeters, on average, for both displays showing no significant differences. In contrast, preferred angles for the two displays are significantly different and this can be interpreted that curvature vary the points focused. Two linear models as functions of sitting eye height are developed to expect preferred tilt angle for each display. Based on the result of overall satisfaction evaluation, curved display is statistically better than flat display. Conclusion: The results show that flat and curved displays are significantly different expect for the viewing posture. However, reasons for preferring curved display are not accurately factorized and the linear models are limited in the experiment condition such as size of display, distance between display and viewer and other physical environmental factors. Further studies on curved displays under more various conditions are required. Application: This study can contribute to use of the curved display in various way.
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J
ESK
J Ergon Soc Korea 2014; 33(3): 191-202
http://dx.doi.org/10.5143/JESK.2014.33.3.191
http://jesk.or.kr eISSN:2093-8462
A Research on Curved Display Comparing to
Flat Display Regarding Posture, Tilt Angle,
Focusing Area and Satisfaction
Sung Hee Ahn, Byungki Jin, Sanghyun Kwon, Myung Hwan Yun
Department of Industrial Engineering, Seoul National University, Seoul, 151-744
Correspondin
g
Author
Myung Hwan Yun
Department of Industrial Engineering,
Seoul National University, Seoul, 151-744
Mobile : +82-2-880-1403
Email : mhy@snu.ac.kr
Received : January 04, 2014
Revised : January 24, 2014
A
ccepted : February 20, 2014
Objective:This study is conducted on the differences between flat and curved
displays with respect to location of focused points, posture and satisfaction as well
as preferred tilt angles.
Background: In order to avoid physical and eye fatigue caused by misplayed sitting
posture, many studies have asserted that the display requires appropriate location,
size and tilt angle as well as curvature. However, most studies have focused on the
work environment and the results are varied in the extent.
Method: Eye height data in sitting posture were collected from 30 participants.
Participants selected the most comfortable viewing angle within the range from 0°
to 12° while watching videos for both curved and flat display. Then, physical and eye
fatigue and overall satisfaction were subjectively evaluated. Lateral diagram describing
viewing display condition was set and used to develop linear models for expecting
the preferred tilt angle.
Results: Due to sitting in the natural viewing posture rather than upright, the eye
height is lowered to about 4.6 centimeters, on average, for both displays showing no
significant differences. In contrast, preferred angles for the two displays are significantl
y
different and this can be interpreted that curvature vary the points focused. Two
linear models as functions of sitting eye height are developed to expect preferred til
t
angle for each display. Based on the result of overall satisfaction evaluation, curved
display is statistically better than flat display.
Conclusion: The results show that flat and curved displays are significantly differen
t
expect for the viewing posture. However, reasons for preferring curved display are
not accurately factorized and the linear models are limited in the experiment
condition such as size of display, distance between display and viewer and othe
r
physical environmental factors. Further studies on curved displays under more various
conditions are required.
Application: This study can contribute to use of the curved display in various way.
Keywords: Curved display, Viewing angle, Display cur vature, Vision, Tilt angle
Copyright@2014 by Ergonomics Society
of Korea. All right reserved.
cc This is an open-access article distributed
under the terms of the Creative Commons
A
ttribution Non-Commercial License (http://
creativecommons.org/licenses/by-nc/3.0/), which
permits unrestricted non-commercial use,
distribution, and reproduction in any medium,
provided the original work is properly cited.
1. Introduction
As technology being developed, it is possible to produce more diverse visual displa
y
terminal (VDT). Accordingly, many studies have been conducted on VDT focusing
on size of screen, resolution, screen height settings or distance between eyes and
192 Sung Hee Ahn, et al. J Ergon Soc Korea
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Screens (Rempel, Willms, Anshel, Jaschinski, & Sheedy, 2007; Seghers, Jochem, & Spaepen, 2003; Shin and Hegde, 2010).
In order to reduce eye fatigue, six extrinsic eye muscles control the position of each eye in general (Kroemer and Hill 1986). The
muscles can be fatigued when displays for TV or computer or mobile phone screens are located inappropriately, and the head
moves to locate the eye on where the fatigue can be relieved. If the user keeps inappropriate posture at this time, his/her neck
may be too strained. In the office, workers do their job by operating computers. VDTs, in particular, is very important regarding
its location, inclination, resolution, and many studies related have been conducted on size, resolution, relative location of user
and the display, inclination, and so on. According to the result, the screens which had larger size and higher resolution bring more
effective results (Shupp, Andrews et al., 2009). Also, it was found that eye fatigue tended to occur more when the display was
located closer than the user prefers (Jaschinski, Heuer et al., 1998). Regarding the height of the display, the results of studies are
not consistent, but they agreed to conclude that the height of displays has to be lower than user eye height to relax eye muscles
and neck muscles (Grandjean, H
ü
nting et al., 1983, Straker and Mekhora 2000, Fostervold 2003). Similar to the studies related to
the height, an inclination of display which changes as a location of displays changes differs in degree between researches (Straker
and Mekhora 2000). Nonetheless, those researches have been limited to the use of displays in office where the 'efficiency first'
principle exists, being lacking in general use out of the office.
Looking at the flow of developments and researches of the technology for VDT, they have been focused on size, resolution or
3D visualization, but they are being extended to connectivity between devices or curvature of the screen (Han 2013). According
to the report written by Han (2013), curved TV screens attracted public attention most at 2013 Consumer Electronics Show (CES),
which is the biggest international exhibition for home appliance and where the most recent technologies for home appliances
are unveiled. The researches related to the curved display have not been needed desperately since the product is hard to realize
because of technical problems. Now the product has been released without demonstrating the superiority.
The curved displays differ from the ones with flat screen; watching the flat displays, the users perceive different viewing distances
when they gaze at the center of the display and the edges of it, and this may induce ocular torsion. As illustrated in Figure 1,
this difference can be reduced by watching curved display. With flat displays, the viewing distance when a user gazes at the
edge of the screen is getting more differed from the distance he/she gazes at the center as the size of screen increases. This
phenomenon occurs less with a large, curved screen. According to a previous study conducted on the curved screen of which
curvature was formed by locating several flat displays, it was found that the display with curvature was more effective than the
flat one (Shupp, Andrews et al., 2009). This result proved curved displays had the reduction effect of the difference of viewing
distance, but the experiment was limited to the office. Moreover, the radius of screen was 762mm, which cannot be applied to
the use of displays in general. Comparing computer displays, TV is not same in terms of size and viewing distance as well as the
Figure 1.
Difference of viewing distance between flat and curved TV
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purpose; TV has larger screen and longer viewing distance than computer VDT.
Therefore, more studies need to be conducted on displays used more generally, such as TV including curved displays, in particular.
As mentioned previously, the studies related to inclination of computer displays for the use in work environment have not been
agreed on the results and it is hard to apply to large displays.
In this experiment, curved and flat displays which can be used as TV in households, identical in the size (55 inches), were
compared in terms of changes in postures during watching TV, preferred tilt angle, gaze point and overall satisfaction and
analyzed.
2. Literature Review
In order to compare two types of TV, evaluation factors were needed to be selected, so investigation into the literature related
to TV and the watching behavior was done.
Watching TV, people normally concentrate their attention to faces, hands or the various movements of them (Smith 2012). The
main subject should be aligned on the intersection of the vertical and horizontal lines, which divide the screen into nine equal
parts for better composition, and this rule is called "Rule of Thirds" (Grill and Scanlon 1983, Krages 2005). However, it is sometimes
hard to keep the subjects on the intersections when the display plays videos such as sports video because the subjects move
very dynamically. In such cases, the users tend to gaze at the center of the display on average (Jin 2013).
A location of a gaze point depends on the gaze direction of which the virtual line is perpendicular to the screen surface. If a tilt
angle is defined as the difference of angle between the vertical line and the display, the angle changes as the gaze point changes.
In other words, there is only one angle corresponding to a particular watching posture if eyes do not look upward nor downward,
so the tilted angle of display will affect the watching posture. Also, fatigue can occur during VDT use (Seghers et al., 2010), and
TV is not the exception. According to the research done by Jin (2013), viewing satisfaction of TV drops as physical fatigue occurs
implying watching posture is directly related to the viewing satisfaction.
Based on the contents above, the experiment was designed to compare curved and flat TV displays for the viewing satisfaction
considering neck and eye fatigue, viewing posture, the main gazing point, and optimum tilt angle.
3. Method
3.1 Hypothesis
The null hypothesis and alternative hypothesis of this study was as follows.
H
0
: There is no significant difference for factors related to watching TV between curved display and flat display.
H
1
: There is significant difference for factors related to watching TV between curved display and flat display.
3.2 Subject
The experiment was conducted targeting 30 participants whose ages were between 20 and 50 years old (male: 24, female: 6).
'Eye height, sitting' is defined as the vertical distance from the sitting side to eye point as shown in Figure 2. In this experiment,
statistics data for eye height (sitting) provided by Size Korea's human dimensions research and distribution project sponsored by
194 Sung Hee Ahn, et al. J Ergon Soc Korea
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Ministry of Knowledge Economy was used. When eye height (sitting on the given couch) was defined as the vertical distance from
the bottom to eye point, 451.5mm, the height of the chair, was added to eye height (sitting on the given couch) of Korean
population to compare the eye height (watching) of the subjects group with ones of Korean population.
3.3 Variables
Control variables were TV size, location, and distance between TV and subjects, and independent variable was type of display
shape; flat and curved. Dependent variables were postures while watching TV preferred tilted angle, main gazing point, and TV
viewing satisfaction. The experiment was designed to analyze the effect of type of display shape on each dependent variable.
3.4 Apparatus
A jig device which could adjust the tilted angle continuously by wireless remote control was developed for this experiment. 55
inch flat TV and curved TV whose curvature rate was 5000mm were placed on the jig device, and the preferred tilted angles
were measured. The angle could be tilted from 0° to 12° and it was recorded every second and saved to text file (Figure 3).
3.5 Procedure
The experiment was conducted targeting flat and curved display. First, after subjects were seated in the 451.5mm seat height
chair and the eye heights (sitting) were measured and guided to watch different videos during over 12 minutes. By a pilot study,
the videos were confirmed that they have no significant difference in terms of eye's fatigue, satisfaction, immersion among
themselves, so the effect of the videos could be prevented.
The distance from TV and chair was 3,400mm. A grid was marked on the other side of the wall, so the degree how much subjects
moved could be calculated quantitatively. While viewing TV, subjects adjusted the tilted angle freely and found the optimal angle
before the videos ended.
Also, the angle data was stored in real-time to figure out the angle adjusting pattern while the video was playing. Then the
viewing satisfaction, visual and physical fatigue, and viewing immersion for the flat display TV were surveyed through questionnaires.
Figure 2.
Description of Eye Height, sitting (left) and Eye location, sitting on the given couch (right)
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After the experiment for the flat display TV, the same experiment for the curved display TV was repeated. Also, lateral view was
taken by video recording to analyze the changes and patterns for the postures during the experiment.
3.6 Expecting viewing angle
The tilted angle is determined by several factors. If the gazing points are same when watching TV, the elements that change the
angle is eye height (seating), TV height, TV length, and distance from TV.
In this experiment, it was assumed that the gazing point was at the lower trisecting line of the screen and the center of the
screen applying golden rule. Figure 4 is the model under the assumption that the gazing point is at the lower trisecting line. In
this case, the tilted angle θ could be calculated by equation (1). When the gazing point varies, it can be calculated by changing
a coefficient of the TV length (X
1
). When the gazing point is at the center of the screen, the coefficient of X
1
should be 1/2.
θ
: tilted angle
X
1
: TV length
X
2
: TV height
H
eye
: Eye height, sitting
d
: Distance from TV
Figure 3.
TV, angle-adjustable jig and recording system
Figure 4.
A diagram when focusing on the lower trisecting line
196 Sung Hee Ahn, et al. J Ergon Soc Korea
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(1)
θ
: tilted angle
X
1
: TV length
X
2
: TV height
H
eye
: Eye height, sitting
d
: Distance from TV
A relationship between the eye height (sitting) and the tilted angle when the gazing point was at the lower trisecting line was
derived by transforming the equation (1). The results were the same as equation (2).
θ
exp
= 0.1599 H
eye
- 11.37 (2)
θ
exp
: expected tilt angle
H
eye
: Eye height (sitting on the couch)
Like the above, a relationship between the eye height (sitting on the couch) and the tilted angle when the gazing point was at
the center of the screen was derived. The results were the same as equation (3).
θ
exp
= 0.1607 H
eye
- 12.85 (3)
θ
exp
: expected tilt angle
H
eye
: Eye height (sitting on the couch)
These results showed that eye height (sitting on the couch) and the preferred tilted angle has perfect linear relationship
regardless of the gazing point, when assuming that TV length, height of the chair, and the distance from TV are same.
4. Results
4.1 Sample representativeness test
In order to verify representability of the participant group, eye height during viewing TV (eye height, sitting on the given couch)
of the participant group was compared to those for Korean population as shown in Table 1.
The Shapiro-Wilk test showed that the eye height of the participants sitting on the given couch were normally distributed (
p
=
0.642). However, the distribution of the eye height of Korean population had approximately 10cm greater than the one of
participants. In the experiment, the males outnumber the females four to one resulting in bias effect in gender. Considering the
effect, the difference became even larger. Later, it was found that the phenomenon was caused by an instrument effect, which
is slumping effect of the couch.
In addition to the analysis of video images, an extra experiment was conducted for verifying degree of slumping and analyzed.
The result indicated that the eye height, sitting on the couch, decreased 11cm, on average, although the values varied depending
on weight and sitting hip breadth of the participants. Reflecting this, the difference of eye height, sitting on the couch, between two
groups could be reduced to 0.7mm by lowering eye height 11cm and adjusting the gender ratio (4:1) as Figure 5 illustrates. That is,
the result of the experiment can be applied to Korean population through verifying the representability of the participant group.
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4.2 Change in posture and eye height
Figure 6 shows a sitting posture in general (left) and the posture sitting on the couch during TV viewing (right). By analyzing
changes in eye height measured before and after the experiment, it decreased 4.5cm and 4.6cm for the flat display and the
curved one, respectively. This was because the posture during TV viewing differed from general sitting posture leading to the
viewing distance increased by about 10cm. Also, paired sample tests were done to inquire whether the curvature affected the
eye height and the result showed no significant difference (
p
= 0.831). Through the result, it was concluded that the effect of the
flat and the curved displays were not different.
Tabl e 1 .
Distribution of
eye height, sitting on the given couch, Korean population (2004)
Participant group
(N=30)
Korean population
(N=6005)
Distribution Eye height, sitting on the
given couch (cm)
Eye height, sitting on the
given couch (cm) Difference (cm)
Maximum 123.0 135.8 12.8
75th Percentile 116.0 126.5 10.5
50th Percentile 114.0 123.2 9.2
25th Percentile 110.9 120.1 9.2
Minimum 103.0 101.6 -1.4
Figure 5.
Box plot for eye height, sitting on the couch, of participant group and Korean population, and for the corrected value
of participant group
198 Sung Hee Ahn, et al. J Ergon Soc Korea
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4.3 Preferred tilted angles
According to the data on the most preferred angle of TV for each participant, for both displays, the participants were commonly
divided into two groups, the one preferring display not tilted and the other preferring tilted display. Regarding degrees of tilt of
them, the displays showed differences; according to the results of the Shapiro-Wilk test, the tilt angles were distributed normally
centered at 6~7° for the flat TV (
p
= 0.127), whereas the angle between 2° and 4° were selected most and the distribution was
skewed to the left for the curved TV (
p
= 0.68) as shown in Figure 7 and Figure 8. Similarly, the average preferred angles of the
flat TV was greater (5.67°) than the curved one (4.56°) According to paired comparison test, the two TVs differed in the preference
of tilt angles (
p
= 0.021, α = 0.05).
4.4 Difference in Focused points
Realistically, there is a gap between the preferred angles selected by the participants and predicted angles. To maximize accuracy
of predicting preferred tilt angle, two cases were compared; one case assuming the gaze point was located at the center and
Fi
g
ure 6.
Posture differences
Fi
g
ure 7.
Fre
q
uenc
y
histo
g
ram, Flat T
V
Fi
g
ure 8.
Fre
q
uenc
y
histo
g
ram, Curved T
V
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another case assuming the gaze point was at the lower trisecting line. The predicted tilt angle was calculated by using equation (1),
section 2.4., and the result is on Table 2. This allowed concluding that the flat display was more likely to correspond to the gaze
point at the lower trisection and the curved display was likely to do to the point at the center. Table 3 represents the variables of
Equation (1) and their values. During the experiment, the distance between the couch and the display is 3,400mm, but 100mm
was added to it in calculating the distance between the eyes and the display (
d'
) as mentioned in section 4.2.
The accuracy increased when the angles are predicted by using Equation (2) and (3) for the flat TV and for the curved TV,
respectively, since the participants gazed at the lower trisection of the former and at the center of the latter. This means the
preferred tilt angle for the flat TV is greater than for the curved one, in general.
4.5 Satisfaction level
According to the survey on satisfaction measured in a 100-point scale, the curved TV satisfied the participants more than the flat
TV with the average value 82.2 and 76.3, respectively. Having with standard deviation of 11.14 (flat) and 8.84 (curved), it can be
inferred that the flat TV induced more variance between the individuals than the curved TV.
Also, the significant difference of satisfaction between the two displays was found by performing a paired t-test was performed
(
p
= 0.004, α = 0.01).
5. Conclusion
In this study an experiment was conducted to compare flat display TV with curved display TV. TV viewing posture changes,
preferred tilted angle, and preference for the type of display were probed.
The results tested the following hypothesis established in 3.1. Null hypothesis was accepted for the TV viewing posture, and
Tabl e 2 .
Probability that the absolute value of error is less than 2° for each focus point
Focus point
Probability that the absolute value of error is less than 2°
Flat display
Center 0.50
Lower trisecting line 0.67
Curved display
Center 0.64
Lower trisecting line 0.37
Tabl e 3 .
Independent variable and constants used
Variable/Constants Description
X
1
: TV length Given, 704mm
X
2
: TV height Given, 511.5mm
H
eye
: Eye height, sitting Independent Variable
d'
': Actual distance from TV Given, 3,500mm
200 Sung Hee Ahn, et al. J Ergon Soc Korea
Journal of the Ergonomics Society of Korea
rejected for the TV preferred tilted angle, main gazing point, satisfaction.
Paired-t test was conducted to analyze the changes in viewing postures. The results showed that there was no significant
difference between two types of displays. So it was figured out that curvature of the display doesn't affect the viewing posture.
In this experiment, there was no particular behavior except the change in eye height (sitting). These results might be caused by
viewing time not long enough and unnatural behavior due to the video recording. This point could be the remaining challenges
of this study.
For the preferred tilted angle, the results were different between curved and flat display. Mean angles of the flat and curved
display were 5.67° and 4.56
° respectively. Also the distribution of the preferred angle for the curved display was tended to be
less than the one for the flat display. This result was consistent to the prediction of the preferred angle meaning the gaze points
of each display are different; the curved display attracted gaze mostly to the middle of the screen, but the gaze point of the flat
one was located at the lower 1/3 point. Gazing at the center helps to look at the entire display at a time. Applying concept of
useful field of view (UFOV), the advantage of the gaze point at the center can be explained. UFOV is defined as the area that the
visual information can be extracted at a brief glance without eye or head movements. Assuming the UFOV is constant, it covers
more area on a display when the gaze point is at the center, comparing when it is not. Therefore, it can be interpreted that the
tendency of users gazing at the center of curved display is more helpful in viewing TV as whole without moving other body
parts. This may be one reason explaining higher score on the curved display.
Moreover, the preferred angle of flat display is always greater referring to Equation (2) and (3) considering reasonable eye height
(< 1,850 cm), yet it is limited to the experimental conditions such as height of the couch or the distance the display. This process
can be applied to other cases with different environmental conditions by modifying coefficients and constants.
This study is worth because it suggests the model that can be modified according to conditions and applied to general population.
Also, the model is linear, so not many data is required to modify the model.
For future studies, slumping effect of a chair resulting in lower eye height should be considered for experimental design. Later, in
addition to a three-dimensional effect, reduction in the viewing distance and newness, more concrete reasons why the curved
TV satisfies users more can be inquired by future studies.
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Author listings
Sung Hee Ahn:
kfcice@snu.ac.kr
Highest degree:
MS, Department of Industrial Engineering, Seoul National University
Position title:
Researcher, Human Interface Systems Lab., Department of Industrial Engineering, Seoul National University
Areas of interest:
Biomechanics, User-Centered Product Design
Byungki Jin:
bkjin01@snu.ac.kr
Highest degree:
BS, Department of Industrial Engineering, Seoul National University
Position title:
PhD candidate, Department of Industrial Engineering, Seoul National University
Areas of interest:
User Interface Design, AR, Product Desgin
Sang Hyun Kwon:
slowband@naver.com
Highest degree:
BS, Department of Industrial Engineering, KAIST
Position title:
PhD candidate, Department of Industrial Engineering, Seoul National University
202 Sung Hee Ahn, et al. J Ergon Soc Korea
Journal of the Ergonomics Society of Korea
Areas of interest:
Human Factors
Myung Hwan Yun:
mhy@snu.ac.kr
Highest degree:
PhD, Penn State University
Position title:
Professor, Department of Industrial Engineering, Seoul National University
Areas of interest:
Human factor, HCI, Affective Engineering, User-Centered Product Design
... Immersiveness is the subjective impression that a viewer has, a feeling of being present in the scene or a feeling of being drawn into the image (Hale and Stanney, 2014). However, most studies so far have focused on technical aspects of curvature (Ahn et al., 2014;Lu et al., 2017;Y. Park, Yoo, Kang and Kim, 2015), and there are only very few studies focusing on the subjective user experience (D. ...
... In general people seem to prefer round shapes more than angular shapes as reported in a study comparing the effect of angularity on preferences by Silvia and Barona (2009). Ahn et al. (2014) compared flat screens with curved screens and found that participants reported a higher level of satisfaction with the curved screen. However, it was unclear from the study why curved screens were preferred over flat ones. ...
... Our findings agree with findings of previous studies that, for video viewing, concave/convex displays are preferred by viewers (e.g. Ahn et al., 2014;Na and Suk, 2016;Pan et al., 2014). As predicted in Hypothesis 3, perceptibility correlated positively with overall preference. ...
Article
Curved displays are believed to create a feeling of immersiveness similar to virtual reality. However systematic studies are needed to demonstrate that this is, in fact, true and under what conditions. In an experimental study 24 participants compared five different displays (concave, convex, hemisphere, sphere and a flat display) in terms of their immersiveness and perceptibility, and they also rated their overall preferences. Both immersive-ness and perceptibility affected overall preference ratings. Participants gave higher preference ratings to the convex and concave displays, which were rated high in immersiveness and perceptibility, but gave lower preference ratings to the hemisphere/spherical display which had high ratings on immersiveness but low ratings on perceptibility. The study results imply that curved displays do indeed create a feeling of immersiveness. Concave and convex displays were rated highly favorably and should receive more attention for applications where visual experience and a feeling of immersiveness is particularly important.
... visual task performance for productivity - Czerwinski et al. (2003) -or user preference for well-being - Na et al. (2015)), or two evaluative aspects (e.g. safety and well-being - Mun et al. (2015) and Ahn et al. (2014); productivity and well-being - Choi et al. (2018) and Wang et al. (2007); and productivity and safety - Lin et al. (2009) and Park et al. (2017)). A study considering all three aspects is necessary for understanding the overall display curvature effects. ...
... Kim et al. (2015) 41.7% respondents who took regular rests, 30.1% took 10 min breaks every 2 h and 14.8% 10 min breaks every 1 h. Previous curvature display studies have used task durations ranging from 12 min to 1 h: 12 min video watching (Ahn et al., 2014), 30 min visual searching (Park et al., 2017), 30 min visual tasks (Lee & Kim, 2016), 60 min video watching (Mun et al., 2015), 55 min visual searching (Luo et al., 2016), and 60 min proofreading (Park et al., 2016a). ...
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This study examined the effects of display curvature and task duration on proofreading performance, visual discomfort, visual fatigue, mental workload, and user satisfaction. Five 27″ rear-screen mock-ups with distinct curvature radii (600R, 1140R, 2000R, 4000R, and flat) were used. Ten individuals per display curvature completed a series of four 15 min comparison-proofreading trials at a 600 mm viewing distance. Only proofreading speed benefited from display curvature, with 600R providing the highest mean proofreading speed. Proofreading speed increased and accuracy decreased for all display curvatures over the 1 h proofreading period. Visual discomfort, visual fatigue, and mental workload increased during the first 15 min of proofreading. A decrease in critical fusion frequency during that period indicated increases in visual fatigue and mental workload. A short break between 15 min proofreading tasks could be considered to prevent further degradation of task performance and ocular health.
... Recently, display technology has rapidly changed from conventional flat-type displays to flexible displays [1][2][3][4][5] such as bended, foldable [6][7][8][9][10][11][12][13], curved [14,15], and rollable [16][17][18][19][20] displays. These evolving display types require the appropriate display materials and process technologies. ...
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Recent display technology has changed substantially from flat-type displays to bended displays. As a result, the lamination process for bonding the panel substrates and bended window glass has become difficult due to the changes in display shape, and the use of optically clear adhesive (OCA) makes it impossible to rework defective substrates due to residue problems. Therefore, it is necessary to research and develop a substrate-surface treatment that maintains the initial adhesion and is reusable via the complete removal of impurities during delamination in order to enable rework. In this paper, the possibility of maintaining adhesive force and reusing substrates was confirmed through the surface treatment of substrates and OCA using various materials. We found that a surface coating and a cooling treatment of additional substrates completely removed the impurities that remained on the substrates during reworking. These results could contribute to improving lamination-process technology and the productivity of the various forms of next-generation displays that are currently under development.
... Of those, eye issues are the single most not unusual grievance. Making use of idea of useful field of view (UFOV) research [6] to provide the benefit of the stare factor on the central may be defined how curved reveal better than flat. UFOV is described as the component that the visual evidence can be pull out at a short test without head or eye motion. ...
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This paper presents the design analysis of distributed control system room with curved monitor. The objective of this research is to seek the possibility of replacement current monitor using eye ergonomic and human factor analysis. The research are backed up with three theories of Fitts's Law, Horopter Theory, and Westheimer's Saccadic Eye Movement Model. Fitts Law used to illustrate the general powers and faults of humans and machines. Horopter used to match another distinctive of our visual ergonomic: the placement of surfaces of monitors. Saccadic eye movements used to describe the express movements of eyes with monitor shape. The survey was conducted to operators seeking possibility to use curved monitor to replace the flat monitor. The researcher used simulator for Boiling Water Reactor (BWR) and its training movies and asking the participant doing the experiment then filling up questionnaires. Participants will be selected from the panel DCS operator doing their job in oil, gas and petrochemical manufacturing plants. The questionnaires are analysed by Rasch Model Analysis, to seek the benefit of curved monitor than flat monitor. Rasch analysis to find internal test reliability and conclusion out the each item analysis on visual ergonomic and human factor interaction.
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Remote simultaneous interpreting (RSI) draws on Information and Communication Technologies to facilitate multilingual communication by connecting conference interpreters to in-presence, virtual or hybrid events. Early solutions for RSI involved interpreters working in interpreting booths with ISO-standardised equipment. However, in recent years, cloud-based solutions for RSI have emerged, with innovative Simultaneous Interpreting Delivery Platforms (SIDPs) at their core, enabling RSI delivery from anywhere. SIDPs recreate the interpreter’s console and work environment (Braun 2019) as a bespoke software/videoconferencing platform with interpretation-focused features. Although initial evaluations of SIDPs were conducted before the Covid-19 pandemic (e.g., DG SCIC 2019), research on RSI (booth-based and software-based) remains limited. Pre-pandemic research shows that RSI is demanding in terms of information processing and mental modelling (Braun 2007; Moser-Mercer 2005), and suggests that the limited visual input available in RSI constitutes a particular problem (Mouzourakis 2006; Seeber et al. 2019). Besides, initial explorations of the cloud-based solutions suggest that there is room for improving the interfaces of widely used SIDPs (Buján and Collard 2021; DG SCIC 2019). The experimental project presented in this paper investigates two aspects of SIDPs: the design of the interpreter interface and the integration of supporting technologies. Drawing on concepts and methods from user experience research and human-computer interaction, we explore what visual information is best suited to support the interpreting process and the interpreter-machine interaction, how this information is best presented in the interface, and how automatic speech recognition can be integrated into an RSI platform to aid/augment the interpreter’s source-text comprehension.
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Displays with panels larger than 30 inches are being provided to workers in corporate settings at an increasing rate. Additionally, some models are offered that have curved panels. This field study was designed to observe user selected position of 34 inch curved and flat displays and determine if there are positioning, user experience and satisfaction differences between pre-presbyopes and presbyope workers who have multifocal vision correction. The results indicate that participants position larger displays a little farther away than displays with a less than 30 inch diagonal. Newer, larger displays did not reduce reports of eye discomfort, but they did significantly reduce reports of neck and shoulder discomfort. Study participants preferred working with the curved display compared to the large flat display.
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The physical nature of cave walls and its impact on Upper Palaeolithic image making and viewing has frequently been invoked in explanations about the function of cave art. The morphological features (convexities, concavities, cracks and ridges) are frequently incorporated into the representations of prey animals that dominate the art, and several studies have attempted to document the relationship between the cave wall and the art in a quantitative manner. One of the effects of such incorporation is that undulating walls will distort the appearance of images as viewers change their viewing position. Was this distortion deliberate or accidental? Until now, the phenomenon has not been investigated quantitatively. We address this here, analysing 54 Late Upper Palaeolithic animal images deriving from three Cantabrian caves, Covalanas, El Pendo and El Castillo. We introduce a novel use for photogrammetry and 3D modelling through documenting the morphology of these caves' walls and establishing the specific relationship between the walls and the art created on them. Our observations suggest that Palaeolithic artists deliberately placed images on very specific topographies. The restricted nature of these choice decisions and the fact that the resulting distortions could have been avoided but were not suggest that the interaction between viewer, art and wall was integral to the way cave art functioned.
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Objective: This study examined the effects of display curvature, presbyopia, and task duration on visual fatigue, task performance, and user satisfaction. Background: Although curved displays have been applied to diverse display products, and some studies reported their benefits, it is still unknown whether the effects of display curvature are presbyopia-specific. Method: Each of 64 individuals (eight nonpresbyopes and eight presbyopes per display curvature) performed four 15-min proofreading tasks at one display curvature radius setting (600R, 1140R, 4000R, and flat; mm). Diverse measurements were obtained to assess visual fatigue, task performance, and user satisfaction. Results: The mean pupil diameter was the largest with 1140R, indicating this curvature radius was associated with the least development of visual fatigue; 600R was comparable with 1140R in terms of pupil diameter. The presbyopic group showed a 28.5% slower proofreading speed compared to the nonpresbyopic group, whereas their proofreading accuracy was comparable. For both groups, the mean visual fatigue increased significantly during the first 15 min of proofreading, as indicated by a decrease of 0.11 mm in the mean pupil diameter, an increase of 3.8 in the mean bulbar conjunctival redness, and an increase of 9.13 in the mean eye complaint questionnaire score. Conclusion: The effect of display curvature was not presbyopia-specific. Low visual fatigue was observed with 1140R and 600R. Application: Display curvature radii near or in the range of 600R and 1140R and frequent breaks are recommended for both presbyopic and nonpresbyopic groups to reduce their visual fatigue due to visual display terminal tasks.
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The purpose of this study was to examine the effects of display curvature and hand length on smartphone usability, which was assessed in terms of grip comfort, immersive feeling, typing performance, and overall satisfaction. A total of 20 younger individuals with the mean (SD) age of 20.8 (2.4) yrs were divided into three hand-size groups (small: 8, medium: 6, large: 6). Two smartphones of the same size were used – one with a flat display and the other with a side-edge curved display. Three tasks (watching video, calling, and texting) were used to evaluate smartphone usability. The smartphones were used in a landscape mode for the first task, and in a portrait mode for the other two. The flat display smartphone provided higher grip comfort during calling (p = 0.008) and texting (p = 0.006) and higher overall satisfaction (p = 0.0002) than the curved display smartphone. The principal component regression (adjusted R2 = 0.49) of overall satisfaction on three principal components comprised of the remaining measures showed that the first principal component on grip comfort was more important than the other two on watching experience and texting performance. It is thus necessary to carefully consider the effect of display curvature on grip comfort when applying curved displays to hand-held devices such as smartphones.
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Computer users have a wide variety of computer display preferences, but a contentious argument has been used in favor of the curved display. In this context, this study investigated the users’ curvature preference for six different content types, and compared the usability of the curved and flat panels in terms of readability performance. A 27-inch bendable display panel was devised for the experiment to enable users to adjust the curvature manually. In the first experiment, the study participants searched for the optimal radii of curvature when the six content types were mounted in sequence on the bendable display, which confirmed the users’ preference for the curved display over the flat display. The following experiment demonstrated that the study participants showed improved readability on the curved display, which supported the study hypothesis. The results of the experiments in this study suggest that the curved display will help improve the work efficiency of consumers.
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As display technology continues to improve, there will be an increasing diversity in the available display form factors and scales. Empirical evaluation of how display attributes affect user perceptions and performance can help designers understand the strengths and weaknesses of different display forms, provide guidance for effectively designing multiple display environments, and offer initial evidence for developing theories of ubiquitous display. Although previous research has shown user performance benefits when tiling multiple monitors to increase the number of pixels, little research has analyzed the performance and behavioral impacts of the form factors of much larger, high-resolution displays. This article presents two experiments in which user performance was evaluated on a high-resolution (96 DPI), high pixel-count (approximately 32 million pixels) display for single-user scenarios in both flat and curved forms. We show that for geospatial visual analytics tasks there is a benefit to larger displays, and a distinct advantage to curving the display to make all portions of the display more accessible to the user. In addition, we found that changing the form factor of the display does have an impact on user perceptions that will have to be considered as new display environments are developed.
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At office workplaces equipped with visual display units (VDU) that were adjustable to various positions relative to the eyes short and long viewing distances from the eyes to the screen were imposed (mean value of about 63 and 92 cm) at two levels of screen height so that the visual target was either at eye level or 18 cm below, on the average. The change from far to near viewing distance produced a larger increase in eyestrain when the VDUs were at eye level. High screens resulted in greater eyestrain than low screens, as shown by correlations over subjects. When operators were free to adjust the most comfortable screen position, the group of 22 participants preferred viewing distances between 60 and 100 cm and vertical inclination of gaze direction between horizontal and -16 degrees downwards. However, within most subjects the range of preferred screen positions was much smaller. Between 3 days during a 1-month period the test-retest correlations of the preferred screen positions were highly significant, both for viewing distance and vertical gaze inclination. When operators were forced to work at a shorter distance than their preferred viewing distance they reported more visual strain. Thus, operators appear to prefer an individual adjustment of the screen relative to the eyes in order to avoid visual strain and discomfort at VDU work.
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Determine the effects of display viewing distance on both the visual and musculoskeletal systems while the text height is held constant across viewing distances. The distance from the eyes to a computer display may affect visual and neck comfort. If the angular size of the characters remains the same, it is recommended that the display be placed at a farther viewing distance (e.g., 70-100 cm). However, in common usage, the character sizes are not adjusted based on viewing distance. Participants under the age of 35 years (N = 24) performed visually demanding tasks using a computer display for 2 hr each at three viewing distances (mean: 52.4, 73.0, and 85.3 cm) while torso and head posture were tracked. At the end of each task, eye accommodation was measured and symptoms were recorded. The near distance was associated with significantly less blurred vision, less dry or irritated eyes, less headache, and improved convergence recovery when compared with the middle and far distances. Participants moved their torsos and heads closer to the monitor at the far distance. If the computer screen character sizes are close to the limits of visual acuity, it is recommended that the computer monitor be positioned between the near (52 cm) and middle (73 cm) distance from the eyes. The location of a computer display should take into account the size of the characters on the screen and the visual acuity of the user.
User-preferred position of the computer display and the keyboard were quantified to determine how the size and/or the number of computer displays (19″, 24″, 27.5″, and dual 19″ LCDs) influence the positioning of the computer workstation components. Nineteen subjects performed a data entry task for 20 minutes with periodic repositioning of the display and the keyboard to their most comfortable setting. Subjects placed displays significantly (p<0.05) further as the size of display changed from 19″ to 27.5″ while maintaining the viewing angle to the top and center of display at or near eye height. Preferred position of the keyboard was not influenced by the display size. Results of this study indicate that the dimensions or adjustability of a computer workstation should be determined with consideration of the display size to accommodate both the keyboard and the display at their most preferred positions. Copyright 2010 by Human Factors and Ergonomics Society. Inc. All rights reserved.
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The intention of most film editing is to create the impression of continuity by editing together discontinuous viewpoints. The continuity editing rules are well established yet there exists an incomplete understanding of their cognitive foundations. This article presents the Attentional Theory of Cinematic Continuity (AToCC), which identifies the critical role visual attention plays in the perception of continuity across cuts and demonstrates how perceptual expectations can be matched across cuts without the need for a coherent representation of the depicted space. The theory explains several key elements of the continuity editing style including match-action, matchedexit/entrances, shot/reverse-shot, the 180° rule, and point-of-view editing. AToCC formalizes insights about viewer cognition that have been latent in the filmmaking community for nearly a century and demonstrates how much vision science in general can learn from film.
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Lower monitor placements, with gaze angles to the centre of the screen 30–45° below the horizontal line are proposed as an alternative to higher monitor placements advocated by prevailing guidelines. A scientific basis for this proposition has been established within a comprehensive theoretical framework, founded on an ecological systemic approach to vision. A review of the literature shows reduced visual strain and a strong tendency towards reduced symptomatology in subjects working with downward gaze. Increased musculoskeletal load is not evident in m. trapezius, while a clinically insignificant increase might be present in some other neck and shoulder muscles. Research studying subjective preferences is inconclusive at present. The evidence indicates that lower monitor placements result in less strain on the total network of muscles involved in visual display unit (VDU) work.Relevance for industryVDUs are widely used in industry. Monitor placement is a critical factor in the discussion about negative health effects associated with VDUs. A review of the present knowledge represents a basis for the development of future guidelines.
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Due to a dramatic increase in musculoskeletal disorders relating to computer use, a number of ergonomics recommendations have been proposed in order to combat this problem. However, some of these recommendations have been conflicting, for example, visual display unit (VDU) monitor placement. This study aimed to investigate the effects of monitor placement in a group of normal subjects. Ten male and ten female subjects within the working age range volunteered to perform a computing task for 20 min in two different VDU monitor placement conditions; high monitor position (HMP) and a low monitor position (LMP). Postural angles (gaze, head, neck, and trunk), normalised electromyography (upper trapezius and cervical and thoracic erector spinae), discomfort (upper body), and individual preference for monitor placement were determined. The results indicated that the gaze, head, neck, and trunk angles in the LMP were significantly greater (more flexed) than those in the HMP. There was a trend for lower levels of electromyographic (EMG) activity for trapezius in the HMP. There were significantly lower levels of EMG activity for cervical and thoracic erector spinae in HMP. There was no difference between the monitor placement conditions on the basis of discomfort ratings. Twelve subjects preferred the HMP compared to 7 for LMP, whilst 1 had no preference. The results of this study suggested that subjects may use a less flexed head, neck and trunk posture and less cervical and erector spinae muscle activity when working with a HMP. However, the compromise between musculoskeletal and visual criteria over prolonged work periods requires further research before a recommendation for VDU height can be justified.Relevance to industryVisual display units are widely used in all industries. The optimisation of their placement is a critical aspect of the human–machine interaction impacting on worker health, satisfaction and performance.
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Recent experiments with 16 male and 16 female subjects indicated that they like to look down rather steeply at an average of −29 below horizontal, s.d. 11·6, when sitting with trunk and head upright. This angle is steeper when the visual target is at 0·50 m distance (−33±11·3) but flatter when the target is at 1·00 m (−24 ± 10·4). When head and trunk are reclined to 105 behind horizontal, the overall angle of the preferred line of sight is reduced to −20 ±11·7 below horizontal, with −23 (± 12·5) at 0·5 m and −16 (±9·6) below horizontal at 1·0 m target distance. These preferred visual angles did not depend on the visual task. The finding that people look down much more steeply than listed in most human engineering design guides has obvious implications for the layout of workplaces where the task has a strong visual component, e.g. at computer workstations.
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A field study was conducted to assess the preferences of VDT operators with regard to their body posture and the settings of an adjustable VDT workstation. Subjects came from four different companies, and the study took place during subjects' customary working activities. Means and ranges of the preferred settings are given. The operators preferred body postures that are distinctly different from those recommended in textbooks and other publications. Some of the workstation settings they preferred also strongly deviate from such recommendations.
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With the increasing use of video display terminals (VDTs), there is growing concern over the corresponding increase in the number of health problems reported. Although much research has focused on identifying the optimal screen height, there is to date no consensus. This study aimed to investigate the effect of prolonged (89 min) VDT work at four different screen heights on head-neck posture, muscle activity and the development of muscle fatigue. The results show that lowering screen height, starting from 15 cm above the baseline (i.e. top of the screen level with eye height while sitting), decreased the ear-eye angle, increased the viewing angle, increased the viewing angle relative to the ear-eye line, and increased the muscle activity of the neck extensor muscles. There were also some significant time effects on postural angles and muscle activity. In this study there were only rare occurrences of muscle fatigue, defined as a simultaneous increase in EMG amplitude and a shift of the EMG power spectrum to lower frequencies. Muscle activity increased significantly in some muscles and for certain screen heights.