Recently, while conducting an evaluation of medical devices to be used at home by patients, I was reminded of the importance and challenge of designing usable displays, in particular, usable displays for small devices. The small displays on these hand-held medical devices must allow the user to accomplish tasks like setting doses, monitoring settings, or reading test results. Having a well-designed display under these circumstances is not just convenient, it’s critical.
Whether you are designing a small display on a hand-held home medical device, like I am discussing here, or a complex display in an airplane cockpit, which we address in the Design CoPilot application, two of the primary human factors issues that should be considered are:
- Can the information be seen?
- Can the information be read and used appropriately?
Although the primary issues, whether the information can be seen and then can be read and used appropriately, seem fairly straightforward, each involves a series of highly interrelated considerations.
Can the information be seen?
When determining whether the information can be seen—the visibility of the display–the following questions should be addressed:
- Are the display size, luminance, orientation, and likely viewing angle all appropriate to allow all expected users to see the information in the environments where it will likely be used?
- Is the location of the display where the users will be able to find the information quickly and see it accurately?
- Is the information on the display distinct enough from the background of the display – is there enough contrast between the information and the background?
- Is the information free from any physical obstructions?
- Is the information free from obstructions from glare and reflections?
Since all of these aspects of visibility play an important role in designing displays, each will be discussed in separate posts throughout the series.
Can the information be read and used appropriately?
Readability is one of the primary human factors considerations when evaluating the information design on any display. There are several factors that determine the readability:
- Character size
- Character style
- Character spacing
- Display orientation
- Use of punctuation
- Color and luminance contrast of information and background
During the series, I will examine how each of these factors contributes to the readability of small displays. Along with this, all of the aspects of information readability and legibility are addressed focusing on cockpit displays in the Design CoPilot application.
I look forward to hearing about your experiences, successes and challenges, in dealing with the design of small displays.