How Big is Too Big for PC Displays?
A Literature Review
Ryan C. Getek
Spring 2007
Index
1Introduction
2Display Technology
2.1Multiple Tiled Displays
2.2Projection
2.3Size and Resolution
3Applications for Large Displays
3.1Problems with Large Displays
3.2Tools for Enhancing Large Display Usability
4Usability Considerations for Very Large Displays
4.1Application Type and Peripheral Information
4.2Environment and Privacy
4.3Availability of Specialized Tools
4.4Physical Display Attributes
5Conclusion
6References
1Introduction
The increasing adoption of large monitors and even multiple monitors might indicate that users perceive a benefit from increased viewable area. Studies confirm that usability benefits do result from larger display size in areas such as visualization and navigation tasks.[1] Although studies show that large displays yield task performance benefits, the authors also note that the challenges in presenting information differ between traditional displays, large displays, and very large displays.[2]
The differences in the ideal display configurations between differing screen sizes leads to a potential limitation in how large a monitor can get and remain useful. For instance, a 40 foot wide monitor would likely prove too large to be practical for most common tasks such as Internet browsing. As the point of diminishing returns is reached with increasingly large screens, the question “how big is too big” becomes important to answer.
Most research related to large display sizes has focused on the benefits of large monitors without consideration for whether the benefits diminish with very large displays. As display costs continue to decrease and the availability of affordable high resolution displays increases, identifying the factors that affect usability as screens get larger becomes critical.
This literature review will begin by looking at display technology including techniques for creating very large displays such as tiling and the use of projection. The importance of size and resolution will also be addressed. Then, the applications for large displays will be identified as well as the problems encountered as display size grows including tools available to mitigate these problems. This will be followed by a discussion on the factors that affect display usability as display size grows, then the conclusion will be presented.
2Display Technology
Display sizes are getting larger. A review of Dell’s site ( reveals that even the entry level Dimension PC’s are available with up to a 22” monitor. Apple’s (store.apple.com) display offerings are even more exclusive, with the only options being a 20”, 23” or 30” display. The reasons behind the shift in size are attributable both to advances in LCD technology and to the enhanced demands for multimedia content that is increasingly integrating TV features with PC functionality.
Cathode Ray Tube (CRT) monitors were prohibitive for expanding display sizes because of the desktop space requirements, power consumption, weight, and cost. As LCD technology became less expensive in the late 90’s, manufacturers began to offer flat LCD displays to consumers at a reasonable price. Mass adoption by consumers has helped decrease the cost of production, and a recent review of Cnet ( reveals that a 22” LCD monitor can be purchased for less than 270 dollars.
In addition to the prospect that LCD displays will continue to get larger, alternatives such as plasma, organic LED (OLED), and other emerging technologies promise to push display technology forward. As new techniques are developed that enable cost effective mass production of very large displays, users may expect to see even bigger screens available at relatively low cost in the future.
Ideally, a series of simple experiments could be performed that would enable the testing of users based upon task performance for very large displays. However, the largest displays currently available are televisions that only go up to about 100 inches, or a little over 8 feet. Alternatively, multiple tiled displays could be used or projection could be performed onto a large surface. As these are the most reasonable current approaches for creating very large displays, the advantages and drawbacks of each will be reviewed. The importance of the relationship between size and resolution will also be explored, as this is a critical component of how information is presented to the user.
2.1Multiple Tiled Displays
One way to create a large display is to take multiple displays and tile them together. Operating systems such as Windows already offer support for multiple monitors, so the user only has to obtain the appropriate displays and video card(s). Some research has already been done in this area with displays of varying sizes, and the results promise to offer the opportunity to understand very large displays by being able to create them in this manner before technology facilitates purchasing a single large display at a reasonable price. Reviews of the range of tiled display offerings have revealed falling cost and an increasing availability of software to support the effective use of this approach.[3]
The use of multiple tiled displays can offer benefits similar to those offered by moving to a single large screen, but there are also drawbacks to consider. Some issues that were noted by Ball et al. include an adjustment period, wasted display space, software and application compatibility problems, and that the bezels between the monitors were distracting.[4] These problems demonstrate that while the use of multiple monitors is not a perfect solution for offering bigger screens, this technique does offer some potential for being able to test display sizes that are larger than are available in a single display.
As manufacturers are encouraged by consumer demand to create large displays in the future, the possibility remains that they might choose to leverage multiple displays as an intermediate way to get there. Some of the problems might be solved if manufacturers do get more involved because issues such as the presence of the bezels could be minimized. In the long term, single large displays seem likely to replace this technique, but the use of multiple monitors currently offers a reasonable way to test displays that are larger than otherwise could be obtained.
2.2Projection
LCD and DLP projectors are becoming common in classrooms, offices, and even home theater systems. They offer a way to display content on a large surface that can be retracted when not in use. Additionally, projectors typically take up less space than a large monitor or television. The limitation on how large the display can get often is based upon the brightness of the bulb and the availability of a large display surface.
Efforts have been made to combine multiple projectors to create large displays. For instance, a collection of three projectors that use a single lamp was demonstrated and shows that such systems could be commercially produced.[5] If manufacturers decide to offer displays that leverage multiple projectors and make them commercially available, there is a potential for enabling very large displays to be provided affordably to a wide range of consumers.
The drawbacks of the use of projection include decreasing image quality and brightness as the projector is moved further away from the display surface, interruption of display for front projection systems when a person or object gets between the projector and display, and decreasing quality as the bulb nears the end of its life. The use of multiple projectors, the availability of rear projection capabilities, and advancing bulb technology are helping to mitigate the impact of these issues.
2.3Size and Resolution
Size and resolution are often conceptually grouped with respect to large displays, but it is important to differentiate between the two. Size is the physical measurement of the space that the display encompasses, usually measured diagonally and in inches. The resolution is the number of pixels represented, and is usually represented by the number of pixels wide by the number of pixels high. For instance, a 15” monitor might have a native resolution of 1280 by 1024, meaning that the screen measures 15 inches diagonally and that there are 1280 pixels across the width and 1024 pixels across the height of the display. A single physical display is typically capable of displaying multiple resolutions, and the specific resolutions possible depend both upon the limitations of the monitor and the capabilities of the video card.
As displays get larger, typically the native resolution gets higher. As larger displays become more prevalent, a wider range of available resolutions become possible and differences in resolution become important because they change how information is displayed to the user. Larger displays do not always necessarily increase resolution, as evidenced in classroom environments where a projector is used to show data such as PowerPoint slides. In such cases, the display is simply stretched across a larger screen.
When resolution is increased, the presentation of data to the user likely changes as well. Figure 1 shows how the presentation of the UMBC homepage differs for two common resolutions on the same physical display. The image at the left shows 1024X768 resolution, while the image at the right shows 1280X1024 resolution.
Figure 1
In the analysis of large displays, resolution plays a significant role in how information appears to users, especially as many users transition PC content to these screens without the use of specialized tools that might take advantage of the increased area.
Both the size of the monitor and the distance of the user from the monitor are also important factors in determining how the content will appear to the user. The visual angle is an important element, which is the width of the display relative to the user. A typical PC monitor that is close to the user might have the same visual angle as a much larger display that is placed further away as shown in Figure 2. The importance of visual angle and issues that arise related to it are discussed later.
Figure 2
Widescreen displays are becoming common in both desktop and laptop computers. The 16:9 ratio (instead of the standard 4:3) is the default for movies. A comparison of the relative difference is shown in Figure 3.
Figure 3
The use of laptops and desktop computers for home theater is increasing, and this may be part of the motivation for manufacturers to move towards these displays. Studies have shown that movie watchers prefer widescreen displays for movies.[6] While less work has been done in evaluating the effects of widescreens on PC users, the greater size may have a similar effect as was observed in the larger monitors that maintained the 4:3 aspect ratio.
The importance of the aspect ratio issue is that as displays get very large, it may become necessary to evaluate the effects both of the varying ratios on ‘normal’ screen sizes, large screens, and very large screens. This will be especially important if the current trend towards convergence of the PC and TV functionality continues, because very large screens that are used for both might reasonably be widescreen because many HDTV units are already using this presentation format.
Alternative aspect ratios that are currently not widely available may also provide usability benefits. For instance, in a study by Czerwinski et al., the optimal visual angle was about 100 degrees wide.[7] In another study by Polys et al., the Software Field of View (SFOV) and associated vertical viewing angle were found to have significant effects on user performance as vertical angle increased.[8] The potential for a difference in benefit between increasing the width of the display and increasing the height of the display for different applications and environments warrants further examination of which aspect ratios offer the best user experience for very large displays. Careful consideration will need to be taken for human physiology with respect to how the eye moves and where information should expand to in order to maximize usability.
3Applications for Large Displays
One application for large displays is analyzing and correlating large volumes of intelligence information. Booker et al. demonstrated that some of the challenges encountered while trying to interpret large sets of multivariate intelligence data can be overcome with large screens.[9] For traditional displays, techniques such as visualization have sought to present large volumes of information in a limited area. While larger displays offer the potential to present high volumes of data such as intelligence information in a single larger viewable area, the organization of the information remains critical to preserve or enhance usability.
Ni et al. demonstrated that bigger display sizes increase performance in an Information-Rich Virtual Environment (IRVE), which built upon other work being performed in the area of wall sized displays.[10] The opportunity for large displays to more accurately represent real world data in an understandable way to users could open up new avenues for communication, especially for users who wish to communicate complex multifaceted data across long distances. This could enable enhanced collaboration and communication between geographically dispersed groups.
Collaborative work environments are a potentially attractive area to employ large displays because multiple users in the same physical area can view the information more easily at the same time and if specialized toolsets are available, multiple users can even interact simultaneously with the interface. Social interaction and the exchange of multimedia information is facilitated by systems such as Dynamo, which was designed to enable collaboration and enhanced social interaction using a large display.[11] There is an intrinsic ability for larger displays to increase usability and encourage interaction, but there is also the ‘wow factor’ of large displays that may contribute towards the tendency of users to prefer them.
In addition to environments where large screens replace traditional screens for work that is already being performed on PC’s, large screens offer a potential opportunity to take paper based work and transition it to a PC. For instance, the introduction of a large screen display with a PC based system into a healthcare environment that had previously used verbal communication or paper journals for communicating patient status during shift changes revealed an improvement in the ability to communicate information quickly and effectively.[12] This example shows how large screens can not only enhance usability for applications that already run on PC’s, but also enable activities that have traditionally been performed manually to be moved onto a PC with a large display.
Maps are well suited for large displays because they are typically scaled in order to fit into the viewable area. Increasing the screen size enables viewing an area without having to scale down the content as much as a smaller screen would require. The ability to see more context and detail simultaneously can enhance the usability of the map interface. In fact, Ball et al. conducted a study on map usability on a large display and found that users found items twice as fast, required less navigation, and were more accurate in completing the tasks.[13]
Baudisch identifies large displays, especially in combination with focus plus context techniques, as a more effective way to view blueprints, architectural drawings, and graphic design components that traditionally have been difficult to display on PC monitors.[14] For these types of objects, being able to see a larger portion of the overall context can be critical for interpreting the details of any given segment. Large displays facilitate viewing a bigger portion of the entire object and can help enhance the understanding of the user.
Tivo and Digital Video Recorder (DVR) units are essentially scaled down computers that facilitate the selection, recording, and viewing of multimedia content. The combination of computers and multimedia entertainment capabilities is a pervasive theme throughout this review because this trend is helping to drive the demand for larger displays on computers that has already affected the mainstream television market. A doctoral dissertation by Heo revealed that the size of the display has an effect on attention, arousal, memory, and user perception of the content being displayed.[15] As such multifaceted effects pervade into PC displays, the presentation of movies and multimedia content may become an important application for large PC displays.
In addition to the application specific benefits, women generally benefit from larger displays even more than men, and this effect might indicate that larger screen sizes can help reduce the gender bias that has traditionally favored males when interacting with computers.[16] If these benefits also extend to broader classes of novice computer users, larger displays may be able to help bridge the gap between expert users and less experienced users. This phenomenon illustrates the potential for large displays to be leveraged for a wide variety of applications and classes of users.