Boost productivity and brighten up the workplace
Think of industrial control panels, and the mind's eye tends to conjure images of unglamorous, functional items acquired to perform their designated tasks with monotonous reliability at the lowest possible cost. Perceptions are changing however, as companies come under increasing pressure to drive up productivity in the workplace, says Iain Kyle of Design LED.
The high ergonomic standards set by consumer electronic products such as the iPhone are showing how greater ease of use and intuitive access to equipment features enable users to accomplish complex tasks more quickly. Bright, graphical, colour displays and large touch-sensitive panels supporting gesture-based controls such as pinch, flick and scroll are among the high-profile innovations now being employed to help users navigate the device's extensive functionality, and to promise outstanding user pleasure and hence win more sales.
Now that large numbers of people are experiencing such high standards from the equipment they use at home and in everyday life, they expect smoother, sleeker, better looking user interfaces from equipment in the workplace. The writing is on the wall for control panels with interfaces that are difficult to understand, awkward to use, and ugly. Modern designs have to deliver a good user experience as well as a high-quality appearance.
More than just looks
At the same time as improving the look and feel of the user interface, however, control panel designers must also maintain high standards of durability and ruggedness necessary to withstand long operational lifetimes and high duty cycles, as well as environmental hazards. These can include shock and vibration, moisture or chemical substances, or exposure to particulates such as debris from industrial processes.
Touch-sensitive switches offer a way to meet demands for an industrial-tough HMI. Compared to conventional user-input devices such as mechanical switches and buttons, touch controls require no apertures to be cut into the front panel. This enables designers to ensure that the control panel is impervious to moisture, liquids or other hazards without incurring high costs to seal the unit. Designers can also create equipment for use in harsher environments where conventional equipment cannot be sealed adequately. A number of touch technologies are in widespread use, including flexible overlays such as those typically fitted to the front of PDAs, that calculate the position of a touch according to changes in electrical resistance.
Capacitive touch sensors, on the other hand, can be made using an array of electrodes embedded in a panel such as glass or polycarbonate. These are generally considered to be more robust than a resistive overlay. The user's finger creates a change in capacitance when approaching the electrode array. The electrodes can be concentrated in a small area to create individual 'buttons' or may cover a larger area to create a touchscreen. A suitable control IC is required, and there are several options on the market including programmable devices that enable designers to create customised switch panels. These can be fully sealed, with a low profile, and are capable of withstanding many years of robust use.
Brightening up the workplace
But control designers need to do more: light and colour are vital ingredients that will enable touch technology to deliver the productive, pleasing user experiences expected by customers from the iPhone generation.
To add illuminations to a control panel has traditionally required an extra PCB carrying lamps or LEDs to be mounted directly behind the panel. This tends to increase the cost, complexity and overall size of the equipment. Among alternatives a CCFL or LED backlight also adds cost and complexity and is not always applicable. An injection-moulded light guide enables designers to eliminate the additional PCB and illuminate selected areas of the panel using LED or incandescent light sources positioned at the edges. The high tooling costs for custom injection mouldings, however, tend to make this approach uneconomical in the low to medium production volumes typical of many industrial or professional products.
A combination of proven processes and innovative techniques now allows ultra-slim light guides to be created in low volumes at competitive cost, and combined with capacitive touch sensors, side-emitting LEDs and an outer graphic in a flexible assembly only 1mm thick. LEDs of any colour can be positioned at the edges of the assembly, allowing designers to create segmented patterns of light in locations corresponding to touch-sensitive areas on the surface. The light guide can also be designed to mix colours, enabling effects such as warnings or change of status.
This technology simplifies the design of highly functional and eye catching touch-sensitive user interfaces. Its unitary construction eliminates the need for a separate PCB and associated mounting hardware. The light-guide or touch-sensor assembly is either incorporated onto the existing PCB or uses a flexible circuit with a tail to connect power and data lines directly to the main processor board.
The light guide is created using screen printing processes similar to those used by the membrane keypad industry, combined with patented innovations to maximise optical performance. The resulting component is capable of illu-minating precisely defined areas on the control panel. In addition, the light guide enables highly uniform illumination over a large surface area. Lighting of consistent colour and intensity is known to create a positive perception of quality, but has been difficult or impossible to achieve using the more established technologies.
By considering the design of the light guide, touch-sensor array, control electronics and the application software together, designers can create interactive features such as controls that are hidden until lit. This can be used to deliver a number of advantages, such as simplified operation, increased productivity or enhanced safety.
There are no hard tooling costs to act as a barrier to using this technology. Hence designers are able to take advantage of its enhanced optical performance and integrated touch sensors at a price comparable to conventional, lower-performing solutions. In addition, since the display is such a highly visible part of the machine, innovative features such as these, as part of a stylish and attractive appearance, will add value and enable products to stand out against more mundane competitors.
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