TDDI: Expanding the Possibilities of Touch Displays in Vehicles
Aug 03, 2020
By John Brady
There are several key forces driving the evolution of transportation, including the vehicles we drive (or, soon enough depending who you ask, not drive) every day. The connected car, enabled by 5G and IoT, promises to deliver new types of data and information to improve safety, comfort, entertainment, and yes, autonomy in the transportation sector.
The automotive industry has progressively invested more in the underlying semiconductor technology to make their products more safe, secure, and in many ways, more like the user experience of other consumer devices such as our mobile phones and home entertainment systems. On top of enhanced safety features enabled by sensors, cameras, navigation aids and automated controls, automakers are looking to leverage connectivity that will allow the driver to view other content such as internet browsing, email, and/or other entertainment content. Consumers expect the same visual, intuitive and tactile experience they enjoy with their mobile devices in their vehicles. This includes the ability to press, pinch, swipe and control functions with virtual knobs.
A key part of this continuing evolution is the display, which has evolved from showing a set of analog gauges and meters to a plethora of digitized information. In fact, in-vehicle displays have been called the fourth screen - the last ‘unconquered’ screen in our daily lives. With the average driver spending close to an hour a day in their car, how information and entertainment is served up on the road is becoming increasingly important.
Today we are witnessing an increased demand for larger screens such as the center infotainment display, instrument clusters, rear seat entertainment, even rear-view camera displays that replace traditional winged style exterior mirrors. Research from IHS Markit shows that the number of vehicles built in North America with display screens measuring seven inches or more has grown by nearly 75% in the past five years to 10.9 million, from 6.3 million. European car makers are on a similar, if not faster trajectory. We are seeing the bar continue to move with 8-inch display the starting point and 11- to 12-inch being more common in the coming years.
In the not-so-distant future we will see ever larger screens, so-called ‘pillar-to-pillar’ screens, which extend across the width of the dashboard to present an integrated display. These will measure up to 56” inches and require even further levels of integration of display and touch technologies.
TDDI presents an efficient way to improve and expand in-vehicle displays
The challenge in automotive is to deliver the desired performance at acceptable price points while addressing varying design needs and meeting more stringent standards than consumer devices. This involves significant technology challenges, which as a long-time supplier of display and touch technology, Synaptics is very familiar with. By combining touch and display, traditionally separate components, into a single IC, in-cell solution, automakers can lower costs and have an excellent user experience in the form factors they need.
Synaptics is a pioneer in how information is displayed and how users interact with it via touch technology – and how to integrate the two functions. Indeed, we originally pioneered and coined the concept of TDDI (Touch and Display Driver Integration) for mobile phone applications based on a single chip architecture. We’ve successfully adapted that same approach for the rigorous automotive sector.
For automotive applications of TDDI, a multi-chip architecture is necessary in order to support larger display and touch area sizes. However, in the case of multi-chip architecture, synchronization among the plurality of chips is the key factor in order to achieve uniform picture quality and accurate touch response. Using TDDI, display integration of the touch interface combines not only the capacitive sensor inside the LCD panel stack-up, but also the ASIC (Application Specific Integrated Circuit) functions of multiple ICs.
As a result, LCD displays enabled by TDDI have emerged as the preferred option for the growing number and sizes of in-vehicle displays. Evolved for the needs of car makers, TDDI integrates the touch controller and display driver in a novel way, reducing component count and simplifying design. By moving the touch sensor from being laminated outside the LCD to embedding the sensor as part of the LCD manufacturing process, LCD makers can lower the cost substantially while improving the optical clarity at the same time. Automotive TDDI solutions being adopted by OEMs and Tiers 1’s today merge sophisticated touch and display technologies into in-cell designs, eliminating the discrete touch sensor by leveraging existing layers in the LCD.
The bottom line for automakers and their display suppliers: TDDI enables touch sensors to be integrated into vehicle displays for thinner, clearer and lower cost screens.
You can read more about our approach to automotive TDDI in Electronic Products Magazine.