The capacitive touch screens: complete record of writing (operation, applications, advantages, disadvantages, quality).
The touch screen technology is widely deployed for the general public in recent years. While at first glance some may consider touch interfaces like science fiction dreamers for computing enthusiasts, it is clear that they are truly part of our daily lives.
A touch interface is nothing magic behind every interactive device hiding advanced techniques. One of the most common technology is based on the model of capacitive touch screen.
Operation of the capacitive
The first question one might ask is: how a capacitive screen?
The capacitive touch screen technology is based on a solid surface such as glass, which is traversed by a gate electrically charged and almost invisible to the naked eye. The accumulation of electric charges on the glass plate at the contact fingers of the user transfers a portion of these fillers in the fingers, which cause a deficiency that can then locate to process information.
The information processing is made by means of a calculation algorithm integrated directly into the device. It determines the point or points of impact (in the case of multi touch), the direction of movement, sometimes the pressure, and acts accordingly.
diagram of capacitive touch screen
A little less in terms techniques, or fingers on a screen create an electrical disturbance, that the rack placed under the glass to identify localized movements and actions. She then makes the connection with what is displayed on the screen at that moment, to reflect the impact of the user and act somewhat as does a mouse on a screen "normal."
Technology applications for capacitive screens
What are capacitive screens and what applications are they used?
The first prototypes of touchscreens have emerged in the 1970s, since they are discreetly integrated into our consumption habits.
There are over 10 years of aircraft using the general-capacitive screens: ATMs, kiosks and booking train tickets are some familiar examples.
The computer also takes advantage of these technologies, we think including graphic tablets and touchpads unavoidable (touchpad) that replace the traditional mouse on some laptops.
In recent years, it is undoubtedly the appearance and development of solid smartphones that have publicized capacitive screens.
Clearly, Apple's iPhone has played a key role at this level since 2007 thanks to ease of use both new and instinctive, attractive design and marketing titanic work, Apple has managed to democratize use capacitive touch screens on mobile phones. the vast majority of current touchscreen phones now uses capacitive screen technology.
For more information: applications for touch screens .
Advantages and disadvantages of the capacitive
Capacitive technology offers a range of benefits that often give him the upper hand over other techniques for implementing a touch screen.
First, the interface of a device with a capacitive screen is much more robust due to its medium: glass is a hard surface which fears that shocks less flexible coating (used for resistive screens )
Moreover, treatment of the material are possible to obtain an effective anti-scratch pad.
Another significant point: the capacitive touch screens are brighter and guarantee transparency very interesting (more than 90% against 75% for resistive screens), a benefit resulting from the thinness of the glass support. The sensitivity of the screen is also more interesting, just touch the touchscreen to get an immediate response.
Technology of multi touch (recognition of multiple contact points and simultaneous) seems logically more appropriate for use as resistive capacitive screens. Indeed, it is simpler to use his 10 fingers simultaneously, rather than requiring several pens each with several fingers for a good grip ...
The capacitance, however, suffers from a number of constraints.
Comparatively, there is a higher rate for capacitive screens, which are not accessible to all budgets. There is also a large screen sensitivity to the presence of water and moisture. It is important to take great care: avoid the rain and cleaning with wet sponge!
The principle of capacitive technology makes it difficult to use these screens other than bare hands, a conductive body being capital to the reactivity of the slab. Have you ever tried to fly an iPhone with a surface other than your finger?
Gloves and stilettos are not permitted, although over the years there was an increase of their consideration.
Determining the quality of a capacitive touch screen
This video compares the quality of the capacitive touch screen of three mobile phones using a simple test: the faithful reproduction of a tracing finger. Two scenarios were considered: a light support on the screen, with the edge of the finger support and more pronounced with a fingertip. The first case evaluates the path with a weak signal and can lead to a more hazardous route.
It is noted that the implementation of a capacitive screen (component selection, display controller, etc..) Is not sufficient to provide an excellent user experience, the signal processing algorithm also plays a predominant role .
That's what we can say at this time of writing this file, the technology of capacitive screens. Innovation helps, manufacturers of capacitive screens are changing their techniques, and find solutions to improve some weak points.
Image sources: Etronics, digitalworld, Wikipedia.
