 Consumer electronics, including mobile phones, GPS units, universal remote controls, MP3 players and laptops are constantly being redesigned to become smaller, include greater functionality and feature newer, more sleek designs. As a result, component designs, particularly switches, must also follow suit. Originally developed with standard 5-way tactile feel or touch pad technologies, switch developments for consumer electronics use have evolved toward designs that include both tactile and sensitive touch features. These designs are being further advanced through the transformation of a touch pad or touch screen into a clickable touch pad or clickable touch screen.
Miniature 4- and 5-way tactile switches were once the ideal navigation solution in handheld multimedia devices. Screens were small, and original tactile solutions were sufficient to manage the few available functions. But as memory increased, quick access to long lists of items became essential. Fast scrolling using a 5-way tactile switch was extremely difficult, so sensitive technologies such as capacitive were used to implement this navigation capability. Yet power consumption and compatibility with pick-and-place equipment remained concerns. Moreover, a balance had to be found between the size of the screen and the size of the navigation device. With the development of large color screens and camera applications, the large surface on the face of the mobile device that capacitive navigators required was no longer feasible. As such, switch manufacturers began developing tactile solutions that combined both sensitive and tactile switch technologies into a single package. Such solutions afford a number of benefits, including decreased size, increased functionality and lower power consumption.
Navigation technologies that feature sensitive touch and tactile technologies in the same package are growing in popularity, and while many are limited to scrolling features with diameters of 24mm, some solutions measure just 10 x 11.5mm while also including the capability of panning in all directions for mapping or browsing. Subsequently, user-friendliness in mobile devices is improved for three primary reasons: small navigation devices mean that the user doesn’t need large finger movements to select features; larger screens result in better readability and access to a greater amount of information; and the combination of sensitive and tactile technologies allows the user to move at a high speed using the sensitive function, while employing the central click and four tactile directions for precision and item selection.
In addition to the increased functionality and user-friendliness afforded by combination switches, such devices are also surface mountable and pick-and-place compatible, making it easy to integrate into the end product, as well as ideal for manufacturing purposes. Along with increased functionality, this type of design utilizes a combination of switch signals to the software in one device rather than adding another pad or component, resulting in a significant amount of space saving. The switch also doesn’t require any additional components such as an analog to digital converter or a dedicated microprocessor. Existing I/O components already needed for other input devices will drive these components through minimum I/O software adaptation, so not only is space minimized and design simplified, but because no additional electronics are required, cost is reduced, which is an important consideration for the consumer market.
 In addition to saving space with the use of fewer electronic components, typical navigation switches are also extremely reduced in thickness – one of the most important dimensions for all mobile products. In terms of power consumption, combination sensitive touch and tactile feel switch control solutions are being designed to consume far less power than typical capacitance or resistive pads.
While navigation switches that combine sensitive touch and tactile technologies were new to the marketplace just months ago, consumer electronics are continuously evolving and requiring even further functionality on larger screens. The limit is nearly reached with touch screens being the full front face of the product. As a result, switch manufacturers began developing clickable touch screens. Sensitivity of the touch screen provides fast access to any item while tactility provides a secured select function and additional combinations such as click and move.
There are several different technologies available on the market today to generate feedback sensation to end users, but all have significant drawbacks, the first one being poor feedback compared to clickable switch technology. Vibration motors generate a low response and variable sensation for a select function, while piezoelectric devices generate very little displacement that is not perceived well by the finger. Both solutions are expensive and consume power. Standard switch technologies applied directly behind the touch screen provide non-uniform force and travel, thus creating a poor user experience.
Following customer demand, a new type of slim switch component based on a specific mechanical structure has been developed. This clickable switch technology provides constant, uniform force among large surfaces, and is highly resistant to shock. Such clickable technology can also improve shock resistance of the LCD module by absorbing part of the energy transferred to the LCD during a drop. Plus, unlike standard switch designs, clickable technology does not consume any power. Mechanically, clickable switch technologies are easy to integrate – some designs are linked to the PC board via just two contact points, the tactile feeling is more precise than alternative navigation switch designs, and such solutions exhibit an extremely long life span – some up to 10 million cycles.
 Because of the versatility and many benefits provided to the consumer by clickable touch screens, such switch technologies can be applied to a variety of consumer electronics products including mobile phones with OLED technology; GPS units with color LCD screens; universal remote controls with EL film technology; PC touch pads reconfigurable with black and white LCD technology; eBooks with electronic ink technology; UMPCs (ultra mobile PCs) with single or dual screens; and MP3 and MP4 players, to name just a few applications. As clickable technologies are highly versatile, they can also be applied to PC touch pads with standard capacitive technology or multi-touch technology. This results in the keys around the touch pad being suppressed, making the touch pad larger than usual and thus more convenient to use.
As consumer electronics, particularly handheld devices, continually evolve, switch functionality must follow suit to keep pace with the increased functionality requirements. Not long after sensitive navigation switches were implemented in consumer electronics did the technology demand shift to clickable touch pad and clickable touch screen capabilities. It’s safe to say that even as consumer electronics designs continue to push the envelope, they will continue to employ advanced switch designs.
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