We will be issuing our current thinking and lessons learned on a variety of design, manufacturing, quality, and post-market surveillance topics that would be pertinent and current on medical devices, digital health, digital therapeutics, and more.
The user interface design of medical device software needs to be user-centric and mission-critical. It is paramount that human-computer interactions maintain consistency, to help users become familiar with and master the correct use of medical devices. Fonts, symbols, charts, and comments used in the software user interface need to be recognizable and prioritize information so that users can respond quickly.
Software user interface design needs to be scalable to meet the requirements of continuous improvement of medical devices. Compatibility is also considered as more devices are expected to interact with one another.
The screen size of the display device is the physical basis of the software user interface design. Usually, the smaller the display device screen size, the more difficult the software user interface design. Still, the display device screen size depends on the intended use of the medical device and the core functions, not the larger the better. User population also needs to be considered when determining the screen size.
Hardware interfaces and software user interfaces are typically designed by different teams, and the former design is often pre-stereotyped before the latter, which is not conducive to software user interface design, so the integrated design of hardware and software interfaces needs to be strengthened.
Manufacturers often adopt the same software user interface design style for the entire product but may not be able to meet the individual requirements of a specific product, so the software user interface design needs to balance commonality with personality.
Software user interface style needs to consider the number of interfaces, interface depth, interface width, interface structure, and other requirements. The software user interface is based on operational tasks, and the number of interfaces should not be excessive, usually less than ten. Interface depth is used to reflect the hierarchical structure of the interface, usually one to three layers.
The width of the interface is used to reflect the number of options contained in an interface, typically three to twelve, typically five to nine. Interface structure includes linear structure, branch structure, mesh structure, and mixed structure, each interface structure has its characteristics, so it is necessary to combine the operational tasks and interface structure characteristics to choose the appropriate interface structure.
Screen layout needs to consider grid alignment, content grading, content partitioning, background, and so on. The screen content is aligned with each other on a grid basis, the partitions are displayed, the different areas are isolated from each other, the appropriate scale and contrast are maintained with the background, and the high priority content is highlighted according to the priority rating, such as position, highlighting.
Fonts need to consider font type, font size, font spacing, alignment, special fonts (such as bold, tilt, underscore), letter case, background contrast, display resolution, string length, etc.
You need to consider the number of colors, color meaning, color matching, and other requirements, such as the environment and associated lighting. The number of colors should not be excessive, usually three to five. Color meanings need to be regulated according to medical device standards and common-sense practices and should not normally allow users to adjust color meanings. A well-matched color enhances display contrast and recognizability. Colors can also be used for content partitioning and status indications.
Engineers need to consider trend display, waveform display, numerical display, and other requirements. Trend displays are used to reflect the trend of parameters over time, both in real-time and non-real-time, to display current and historical parameters, and to adjust time intervals.
Waveform display is like trend display, often used for short-term real-time display of parameters, need to consider the number, the number of cycles, resolution, line width, color, background color, freeze, refresh, scale, comparison, and other requirements. The numeric display shows only the current value of the parameters, considering font, color, highlight, flicker, position, etc., and the flashing frequency is usually 1-3 Hz.
Human-computer interaction includes, but is not limited to, menus, direct operations, dialog boxes, command lines, data entry, touch screens, etc., and the software user interface design needs to choose the appropriate mode of interaction according to the intended Users and use of medical devices, usage scenarios, and core functions, considering the requirements of interaction speed, compatibility, consistency, etc.
Data entry should be complete, accurate, and efficient, considering input areas, comments, alignment, array arrangement, automatic input and inspection, user modification, and inspection requirements. The input area identifies the area size, data format requirements, and highlights. Comments explicitly enter examples, parameter units, abbreviations, location, and other requirements, where parameter units cannot be mixed, using industry-recognized abbreviations. Arrays are usually arranged in narrow columns. Automatic input and inspection of a clear range of values and can be modified and checked by the user.
Screen interaction needs to consider touch screen, on-screen keyboard, soft keyboard, and other requirements. The on-screen keyboard needs to consider automatic display and hiding, key layout, information feedback, and so on. As a combination of hardware and software, the software and keyboard need to consider the requirements of location alignment, meaning the same, information identification, etc., and the associated software and hardware use the same color, symbol, and other identification.
User support needs to consider operational guidelines, error prevention, semantics, priorities, pop-ups, charts, animations, consistency, and more. The operating instructions are as step-by-step as possible, especially for new users. Error protection can be used in automatic inspection, user inspection, and so on. The language is easy to understand and highlights high-priority information. Symbols, terms, abbreviations, and instructions, labels, and user training materials are used in the software user interface.
As with any design, the user population and environment need to be central in all decisions within the noted points above.