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Collection of small display devices

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 … Continue reading

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Collection of small display devices

When designing small device displays, factors such as the size, contrast, and brightness of the display are frequently addressed. However, one factor that is often not given enough consideration is the impact of glare and reflections on visibility. What creates glare and reflection? The potential for glare and reflections is impacted by the viewing distances, viewing angles, luminance, reflectance, direct lighting, ambient lighting, and indirect lighting expected during use. In controlled environments like an airplane flight deck, glare and reflection problems can be addressed by eliminating the source of the glare through adjusting or filtering the lighting conditions because they are part of the overall design (this is described in detail in areas of the Design CoPilot application). However, when addressing devices used in the home, lighting conditions are not under the control of the designer. So, what can be done to reduce the likelihood of glare and reflections for … Continue reading

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Collection of small display devices

When creating a display on a small device, how large or small should your characters be?  The size of alphanumeric characters affects the readability of information on the display. The size of an alphanumeric character is determined by three features: stroke width: distance across a stroke line used to form an individual character character width: distance across an individual character from one side to another character height: full vertical distance between the top and bottom elements of a character Stroke width Stroke width should be equal for all characters of equal height on a display.  Stroke width-to-height ratio is the ratio of the thickness of the stroke used to form an individual character and the measured height of the character.  It is recommended that stroke width-to-height ratio be 1:6 to 1:8 for black text on a white background under adequate lighting and 1:8 to 1:10 for white text on a … Continue reading

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