When is a silicone rubber keypad (SRK) the best user-interface option?

When it’s time to design a user interface for your product, you might be faced with choosing between a membrane switch and a silicone rubber keypad (SRK).   

Both an SRK and a membrane switch offer important benefits. To aid your decision, compare the pros and cons of each in terms of three different buckets: construction, environment, and operator use.  

Construction offers insight into your user-interface application.  

Both an SRK and membrane switch are sealed. This means that you won’t have to worry about the ingress of water, dust, or other contaminants, regardless of your decision.  

The construction of a membrane switch does offer some benefits that you won’t find in an SRK. The membrane switch is easier to clean, and its slim profile is useful when space and weight limitations exist.   

Also, the plug-and-play design of a membrane switch simplifies repair or replacement.

From a construction standpoint, the membrane switch and the SRK can both be affixed directly to a printed circuit board. Or you can mount an SRK onto a membrane switch. Your choice will be dependent on other factors, including environment and operator use.  

Environment factors into the selection of a user interface. 

The construction and design of membrane switches make them suitable for medical devices, industrial controls, telecom applications, and household appliances. In part, this is because of their slim profile and protected graphics. 

SRKs can also be used in several of the above environments. However, because they offer a larger area and key height, they are often the user interface of choice for safety products, HVAC equipment, and consumer electronics.   

Operator use is an important consideration of user-interface design.  

Both SRKs and membrane switches can be customized to support your needs, but two factors stand out in the comparison of operator use:  

• integrated vs first-surface graphics 
• tactile preferences 

If long-lasting branding or safety instructions are crucial for your application, then a membrane switch could be a better option. Membrane switch design uses integrated graphics, so your graphics will not fade, regardless of the millions of actuations that are supported by a membrane switch.  

An SRK has first-surface graphics. (Think of a TV remote control or another application in which the user makes direct contact with the graphics.) Over time, the graphics will wear.   

On the other hand, a rubber keypad can be a friendlier option. The compression-molded construction offers superior ergonomics and greater tactile feedback.  

If you find that an SRK is suitable for your application, you will be pleased to know that you will receive high reliability at a low cost.   

Please feel free to contact us at salesengineer@cubbison.com to discuss whether an SRK or membrane switch might be best for your user-interface application. 

Other membrane switch resources:

Membrane switches improve versatility and serviceability of HMI

6 tips for optimal membrane switch design