‘Switch' to Functionality, Performance, and Energy Efficiency
As an appliance gateway, switch solutions must be multi-functional: desirable appearance, feel and sound, with optimized aesthetics, ergonomics and performance.
User interface is an extremely important aspect of any appliance. The look (design) and feel (functionality) of a modern appliance can make or break its acceptance in the eyes of the consumer.
An electromechanical switch is one of the first things a potential buyer will push, pull or turn when looking to purchase an appliance; yet these devices are often one of the last items a design engineer considers. Whether designing an on/off, stop or control switch for a washing machine, dishwasher, refrigerator, microwave or coffee pot, electromechanical switches should ideally add to an end product’s aesthetics and ergonomics, as well as its functionality. In addition, consumers continue to demand modern appliances that implement new technologies to increase both energy efficiency and performance, while lowering costs.
Combining Aesthetics and Ergonomics with Functionality
As the gateway to an appliance, a switch solution must have a desirable appearance, feel and sound. Switch manufacturers must work closely with appliance makers to optimize aesthetics, ergonomics and performance. Recently, an appliance maker requested a dual-action tactile switch used for pre-selection or to “wake up” a system from standby before getting an input from a user. The preference was that the switch should not have any tactile feel or sound for the first action, while the second action had to provide a smooth tactile feel and a click to confirm actuation. The switch solution needed to be easy to integrate, small in size and cost-effective.
Such a switch design is currently being developed by switch manufacturers. The KSC S Series dual-action tactile switch from C&K, for example, provides a single-switch solution that meets the needs of appliance original equipment manufacturers or OEMs. The dual-action tactile switch delivered the desired double action with the different tactile effects packaged in the same switch unit. The device offers a pre-selection actuation force of 1.5N (or less) and did not feature a tactile feel via a spring function. The user receives a visual or voice feedback from the system to confirm which function is pre-selected. The second action delivers the selection of the function with a smooth tactile feel as well as sound confirmation of the actuation. The switch design provides engineers the freedom for new ergonomics and offers customizable haptics and sound.
Increasing Energy Efficiency: Zero Power Consumption Switches
Consumers demand appliances that provide new features and functions while reducing power consumption and overall costs. Meeting energy efficiency requirements can be challenging for modern appliance makers. Until recently, only modest measures aimed at reducing appliance power consumption while not in use were employed. To help appliance designers reach energy efficiency goals, switch manufacturers have developed sophisticated switches that power down the appliance when in its “sleep mode,” effectively reducing the appliance’s power consumption to zero watts.
Providing the same haptics or sense of touch and ergonomics as a tactile switch, including quiet operation and positive actuation, these power pushbutton switches not only provide for zero-watt power drain when the appliance is idle or in sleep mode, but they also can handle transient voltage events. Unlike tactile switches, these energy-saving pushbutton switches are capable of carrying up to two amps of current while still protecting appliances from inrush loads upon appliance power/wake-up. These switches are available in a variety of connection options including SMD, THT, and wire leads with or without connectors.
These switches exceed the European Union regulation for power consumption, as stated in the Annex II of the Commission regulation No 1275/2008, by completely shutting off the appliance and limiting any power drain. This directive was implemented by the European Parliament with regard to eco-design requirements for standby and off-mode electric power consumption of electrical and electronic household and office equipment. The directive states that, by 2014, power consumption of any electrical or electronic household and office equipment in any “off-mode” condition shall not exceed 0.50 watts. In addition, the power consumption of equipment in any condition providing only a reactivation function; or providing only a reactivation function and a mere indication of enabled reactivation function, shall not exceed 0.50 watts or 1.0 Watts if a status display is needed.
Implementing New Technologies
Consumers are by now familiar with touchscreens in their smartphones, vehicle infotainment systems, navigation/GPS systems and even computer monitors. Touchscreens can now be implemented into almost any electronic device, including modern appliances. This “clicker” function can be enabled with any touch-sensitive surface, and provides uniform haptics over any surface. The simple mechanical system integrates low-profile tactile switches with the actuating superstructure to provide a clickable touch sensing system. Based on a structure with supporting points, the actuator collects and transmits the force from the touching surface to the switch with a minimum of distortion or power consumption. Pressure on any surface will apply a force on the supporting points at the edge, which will then in turn send back the force to middle arms and then to the appropriate tact switch. The technology is more efficient than “hinged” solutions by providing a smooth and uniform click. Multiple configurations, structures and profiles can be developed depending on the application and room available for integration, from 2.5mm to 10mm.
In addition, the clicker technology can combine with multiple key areas based on the same actuating surface. The keys/buttons are managed via touch sensing in that each area is used for pre-selection of the function. Selecting the function is managed with actuation on the whole surface. The main benefit is that instead of managing separated keys/buttons, the unit can be managed by a single flush surface with haptics, reducing integration issues and simplifying some features like key alignment, backlighting, tactile difference between keys.
A Matter of Touch
Each appliance has different performance requirements, external presentations, internal spacing, and footprint restrictions. As such, each application dictates different packaging and orientation of switches to achieve the functional and performance objectives. In addition, appliance makers mandate specific switch haptics, ergonomics, aesthetics, actuation force, size and cost parameters. Working closely with the switch manufacturer to solve design problems and implement customized performance requirements can yield faster time-to-market by streamlining the prototyping and production ramp-up stages thereby bringing the finished product to market more quickly.
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