Custom Touch Solutions

ENVIROMENTAL ISSUES IN TOUCH SCREEN DESIGN

On a separate note, it is worth mentioning that advanced features such as water resistance, thick cover glass, anti-noise, etc., will have an impact on the smooth maneuvering of the touch panel. As the saying goes, “You can’t have the best of both worlds.” That is why we offer distinct types of control boards to suit the diverse needs of different customers. The Avnet Embedded team will continue to improve and innovate in order to create quality products that meet customer requirements.

PCAP (PCI) TOUCH SCREEN STRUCTURES

Avnet Embedded offers 3 type  PCI touch panels: GFFF (Glass-Film-Film-Film) and GFF (Glass-Film-Film) GFFG (Glass-Film-Film-Glass). Size range of PCI touch panels in GFFF structure are designed in medium to large sizes that ranges from 8.4″ to 21,5″, and the sizes of PCI touch panels in GFF structure range from 3.5″ to 7″ with matching COF tail. The main consideration of GFFF PCI touch panel structure is to prevent the noise interference generated from the LCD monitor, for which may affect the operating accuracy of PCI touch panels. In order to avoid the noise interference, EMI shielding is added on the bottom layer of GFFF PCI touch panels, and allowing 0.5mm space between the PCI touch panel and LCD monitor as the standard distance for PCI touch panels in GFFF structure. In the Q2 of this year, we will progressively launch medium size PCI touch panel in GFF structure. If the product allows the distance between the PCI touch panel and LCD monitor in 1-2 mm, and the touch panel can be operated normally after installing the GFF structure of PCI touch panel, then considering using AMT’s PCI touch panel in GFF structure is welcome.

CUSTOM SPECIFIC DECOR GLASS AVAILABLE FROM AVNET EMBEDDED

Both of standard plain glass and standard décor glass with black printed around the perimeter are available in Avnet Embedded , décor glass can be customized according to your needs, Anti-Glare and Anti-Reflection finished coating on cover glass can be customized. Front Glass types available Soda lime 0,55/0,7/1,1/2/3/4/5/6 mm, Chemically strenghtened (<=3 mm), Heat strenghtened (>=3 mm) or Safety (>=4 mm). The other option is Gorilla Glass 0,55/0,7/1,0/1,1/2mm. Glass type can be V-Band AR or U-Band AR. Optical bonding is improving ambient contrast ratio, better thermal conductivity. Optical bonding prevents water condensation and other contamination. Optical bonding is resistant to extreme conditions and for UV radiation. Also it makes your product shock and vibration resistant.
Avnet EMbedded’s PCI touch panel is characterised by providing a small number of diversified designs with matching PCI control board which fulfills various needs of new touch products. If you require that analog and key function should exist in the same touch product or having other various demands, Avnet can satisfy your needs and demands. Meanwhile, Avnet Embedded also offers standard PCI touch panels in AFFF (OCA-Film-Film-Film) or AFF (OCA-Film-Film) structure. It enables customer using their own décor glass design to be laminated on the AFFF or AFF PCI touch panel by selected partner or distributors in their local. Providing diversified options to customers are our business philosophy, in which we can create different market niche to different customers through the unique characteristics of each touch product.

EMR, EMS, EMI PROBLEMS IN TOUCH SCREEN DESIGN

Electromagnetic radiation (EMR) is prevalent in our living environment, for instance, radio stations, mobile phone towers, fluorescent lighting, electric soldering guns, TV screens, computers, etc. EMR can have an influence on most electrical or electronic devices. In terms of Projected Capacitive Input (PCI) touch panels, sources of interference could generate electromagnetic fields through the human body or other conductive objects and disrupt the proper functioning of touch devices since they are maneuvered by human fingers, resulting in false touch events or malfunctions. Interference has therefore been a main challenge in the applications of pro-cap touch products.

INTERFERENCE TOLERANT PCI DESIGN

Avnet Embedded industrial PCI controllers are designed to meet the needs of divergent industrial applications. To this end, we have developed frequency hopping techniques that can avert noise interference and allow for smooth maneuvering of PCI panels. We have also designed high-spec products that meet rigorous EMC standards. International EMC standards require that electromagnetic interference (EMI) and electromagnetic susceptibility (EMS) be tested with different methods within various frequency ranges. Because electronic and electrical devices can be not only the sources of interference but also the victims of interference, EMC testing encompasses EMI and EMS testing. EMS testing includes Conducted Susceptibility (CS) tests and Radiated Susceptibility (RS) tests.

Take Conducted Susceptibility (CS) Tests for the IEC61000-4-6 standard as an example. RF voltage is directly injected into the power cord or signal cable. There are three testing levels: 1Vrms, 3Vrms, and 10Vrms. The frequency range is 150 kHz to 80 MHz. In Radiated Susceptibility (RS) Tests, for instance, the IEC61000-4-3 standard requires the testing of the device’s radiated susceptibility to the specified spectral components and radiation field intensities. RF signals are radiated through the antenna to generate interference to the device under test. The interference frequency range is 80 MHz to 1GHz. There are three testing levels: 1V/m, 3V/m, and 10V/m.

NEW EMC TOLERANT PCI SERIES

New P2 series control boards (PM1300A, PM1201, PM1400) are supported by enhanced hardware protection and firmware algorithms, as well as our unique frequency hopping techniques. Our standard specifications meet the requirements for 3V RS and CS testing environment. In mid-April we will be launching two special high-spec controllers with boosted EMC robustness: PM1302, which supports 8.4″ to 10.5″ PCI touch panels, and PM1401, which supports 12″ to 15.15″ PCI touch panels. Their EMC specs will meet the requirements for 10Vrms CS testing environment and 10V/m RS testing environment.

SOFTWARE COMPABILITY

Embedded Linux System is used in handheld devices, and media players. This type of system differs from the desktop hardware structure in several ways, such as the use of ARM, and is characterised by its low costs, high performance, and low energy. Embedded Linux includes Android, Tizen, and many systems that use Qt framework to develop GUI. These systems have become more widely used in recent years as the hardware performance increases, and PenMount is committed to offering timely and complete support services accordingly.

The nature of the ARM architecture commonly used in Embedded Linux is distinctly different from that of the x86 architecture used in desktop computers. Customers are therefore unable to use the x86 Linux drivers provided on these platforms directly. Taking into account the diversity of the embedded platforms, Avnet Embedded decided to provide customers the source code for drivers. Clients can obtain source code by providing relevant documents.

In addition, since embedded Linux is normally stored in ROM and cannot be altered easily, customers are not able to install drivers directly into the existing operation system. After obtaining the source code, customers can follow the user guide and manually integrate the source code to the system core. Then the system can be reconfigured and ROM can be updated.

If customers use Android system, Avnet offers not only the basic drivers but also additional apps. For instance, the drawing program provides a testing function for multi touch, allowing users to draw lines and indicate the touch coordinates. Also, PCIMSet Tool program PCI controller related setting functions so that customers can conduct tests on the end products directly.

Avnet Embedded also provides support services for clients who use Qt framework to develop GUI. Early Qt used touch control as a mouse, and could thus only support single-point touch control. For clients who require the support of multi-touch control, Avnet recommends adopting Qt 4.8 or later versions with using the built-in multi-touch enabled plug-ins for software development.

Customers who use other embedded Linux such as Tizen, uClinux, or Chromium OS can refer to the user guides provided by. They can also contact Avnet Embedded should any additional assistance be needed.

In all applications Avnet Embedded trained field application engineers (FAE’s)are working with customers to get the best possible touch screen design for the application. Avnet Embedded´s FAE’s are having the tools and knowledge to give customers the right support on customer site.

TOUCH SCREEN INTEGRATION

There are basically 2-ways to integrate the touch screen. Tape bonding and Optical bonding.
Tape bonding is cheaper way to do this but it has some disadvantages compared to optical bonding. With optical bonding there is no air gap left between the display and touch screen. Optical bonding is improving ambient contrast ratio, better thermal conductivity. Optical bonding prevents water condensation and other contamination. Optical bonding is resistant to extreme conditions and for UV radiation. Also it makes your product shock and vibration resistant. Avnet Embedded is having integration capabilities in Asia and also an facility in Europe. Avnet Embedded´s European facility is located in conjunction with Avnet warehouse in Tongeren, Belgium. In our facility we can give flexible support for our customers in their display and touch screen integration demands.

WHAT TO DO NEXT?

If you have a touch screen need in your product please contact your nearest Avnet Embedded office. We will help you all the way from selection of the right touch screen and technical support to the production phase with the best logistics solutions.