The art of designing TFT modules in America is trending downward. It doesn’t have to.

In today’s rapidly evolving tech landscape, engineers may not be as well-informed on TFT module optimization as counterparts in Asia. (TFT modules are a type of liquid crystal display panel.) The knowledge gap can be attributed to various factors, leading to American-based EMS providers to operate with a less comprehensive understanding of the latest TFT technology. To the American EMS, it is worth considering the discrepancies in knowledge and areas to focus on.

Over the past decade, the expertise surrounding TFT module design in the US appears to have diminished, largely due to increasing operational costs. Asian TFT manufacturers, feeling the pressure of rising operations and travel costs, have cut back on sending engineers and application specialists to the US for direct technical transfer. American engineers have also scaled back travel to Asia, further limiting face-to-face collaboration and knowledge exchanges.

Due to the lack of physical interaction between US EMS providers and Asian manufacturers, a loss of technical exchanges and visual performance comparatives have occurred. This condition has downgraded the performance of TFT Modules as well as the visual "shelf appeal" of TFT Modules designed for the US market. As a result, American-based engineers are designing box-build products with TFT modules out-of-line with specifications, leading to a loss of opportunity to optimize the TFT module. This raises the question: How can American EMS providers bridge the gap and better integrate cutting-edge display technologies into their designs?

Distinct Subsystems

TFT displays are made up of distinct subsystems, each of which plays a crucial role in determining the module’s overall performance. These include components like TFT glass panels, backlighting, IC interface protocols and mechanical construction. With a nearly unlimited amount of possible design configurations available, engineers must account for factors such as display resolution, display speed, visual acuity, environmental conditions (indoor versus outdoor, temperature, humidity), power consumption, impact survivability and various forms of external protection (e.g., ESD proofing, EMI/RFI attenuation).

With all application parameters carefully considered, it’s possible to develop a highly optimized, robust TFT module that meets the application’s specific needs. These important factors may not be fully addressed with the current knowledge gap, however. In some cases, they're not addressed at all.

Modular Construction

One of the most insightful voices in the TFT module industry is Jack Ng, founder and CEO of Intec Display, a Malaysian-based TFT design and manufacturing company. With over 30 years of experience exclusively in the display industry, Ng is deeply familiar with both American and Asian markets. He holds a mechanical engineering degree from the University of Arkansas, which strengthened his understanding of the technology differences and commercial tendencies between the regions’ respective approaches to TFT display design.

According to Ng, one of the most common misconceptions among US-based engineers is that TFT modules are fixed in design with only minor tweaking or modifications possible. In fact, as Ng points out, TFT module construction is highly modular, consisting of multiple subsystems that can be tailored to meet specific requirements. Each subsystem – such as the TFT glass, touch panel sensors, all ICs and backlighting – is customizable in terms of components, materials, configurations and software protocols.

Ng emphasizes that TFT modules can be fully optimized without necessarily increasing material or labor costs. The secret lies in selecting the right components and materials to match the specific application requirements. With a clear understanding of the application and the desired specifications, EMS providers can provide key guidelines to develop the right specification.

Besides providing the TFT module supplier with technical demands, it is just as useful to indicate what specifications are not fixed, such as display driver ICs. Ng stresses this as his top question of his customers, “Once we know what specifications are necessary or flexible, we will select the most cost effective and ease-in-supply chain IC and component solutions.”

Through careful optimization, engineers can enhance the visual quality of the display, which in turn adds significant value to the final product. As Ng suggests, this optimization process involves building a precise specification, evaluating each design point and selecting the appropriate components to achieve the best possible performance. “Frankly, I don’t understand why TFT module manufacturers limit their services to their customer base,” Ng stated, referring to the complete opposite of his business mantra.

“American-based EMS engineers begin their search of TFT product by viewing TFT providers’ websites and will make the choice based on best-case specifications,” Ng added. “A good percentage of off the shelf part numbers listed online are using designs that are 3 to 5 years old, some have EOL ICs or TFT glass.”

A Checklist for TFT Module Design Optimization

To achieve a perfectly optimized TFT module, engineers should consider the following factors, keeping in mind the environmental conditions and specific needs of the application:

• TFT glass: Resolution, video speed, contrast, color gamut, temperatures, viewing angles, interfacing software
• Touch panel sensor: Touch point resolution, software interface, noise suppression, algorithm and sensitivity adjustments
• ICs for TFT glass and TP sensors: Long-term availability, interface software compatibility
• Backlighting: Intensity, longevity, power management, reliability, sunlight readability, selective dimming
• PCBA on flex or FR-4 substrate: Based on mechanical configuration, with necessary ICs and power circuits
• OCA or air bonding: To reduce reflection and enhance visual clarity
• Cover lens: Impact, scratch and chemical resistance, designed specifically for the application
• Connectors and cables: Type and placement based on the mechanical layout and connections
• Environmental factors: Operating and storage temperatures, liquid exposure, debris, UV exposure

The gap in understanding TFT module design between American EMS providers and their Asian counterparts will not subside without recognizing it exists. Many American engineers may not fully grasp the flexibility and potential for customization within TFT modules, leading to missed opportunities for optimization. With a deeper understanding of the latest technology in conjunction to a concentrated effort to analyze the application itself, however, American EMS companies will gain the ability to make a significant improvement to the all-important TFT module. As a result, the EMS company’s value-add contributions can be realized.

Joe Fama is a business consultant with more than 40 years’ experience with multinational EMS and OEM companies. He currently is a consultant to Intec Display; jfama@intecdisplay.my.

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