Which touch technologies come into question
Since there is no touch technology that fully meets all the necessary properties of medical devices, the selection must be made according to the application and the associated priority of the properties. The following questions will help to better determine the technology in question.
When selecting the right touch technology, it is important to compare its advantages and disadvantages with the requirements for the medical device. Electromagnetic compatibility is a critical issue in all touch technologies that rely on projection of an electromagnetic field through the surface of the touch panel.
EMC-compatible touchscreens are mandatory
Interference with the display due to electromagnetic interference fields has a direct effect on the functionality of the touch. For example, a PCAP touchscreen is rather unsuitable for safety-critical applications in medical technology or environments in which a large number of medical devices are parked in a confined space, as unwanted touch inputs can be triggered in the event of electromagnetic interference.
EMC non-critical, resistive touchscreens
Resistive touchscreens, on the other hand, are not critical in terms of electromagnetic interference. Of course, our touch system specialists for medical technology will advise you comprehensively and application-specifically on the selection of suitable touch technologies, on the construction and conception of intuitive operation as well as on the design and design of resistive or projected capacitive touch systems with single-touch, dual-touch or multi-touch functionality.
Questionnaire
Your answers to the following questions will help you identify the right touchscreen technology for the desired application.
| Size: | What size is needed? |
|---|---|
| Requirements: | Which functionalities are desired? |
| Input Method: | Finger, pen or glove? |
| Number of touch points: | Single-, dual-, or multi-touch? |
| Response Time: | How fast does the touch have to react? |
| Error correction: | Under what conditions are entries made? |
| Surroundings: | What are the environmental conditions (temperature, humidity, light, vibration)? |
| EMC: | Are other devices with strong electromagnetic radiation placed near a device with a touch screen? |
| Durability: | What is the desired service life? |
| Robustness: | Resistant to scratches, chemicals, shatterproof? |
| Complexity: | Custom-made or standard application? |
| Legal requirements: | What standards and legal requirements have to be met? |
| Spare parts: | Will replacement parts have to be available in the future? |
| Unit costs: | What is the possible budget for the HMI as a component? |
| Power consumption: | How critical are a few milliwatts of power consumption? |