Free-form touch displays for innovative interaction

At electronica 2018, display specialist Tianma is going to present new prototypes and process technologies with which developers and designers can now design displays in line with their individual ideas, following the classic design motto ‘form follows function’.

Up to now, these displays have been generally rectangular in shape. Tianma has been constantly developing new technologies to be able to manufacture such displays in almost any shape in the future. These technology advances are highly appreciated by manufacturers of consumer devices and wearables. In addition, numerous industrial applications are conceivable where the choice of free-form displays follows a technical ratio, for example in case of ergonomically shaped products or medical devices.

To demonstrate the possibilities for producing such new and unconventionally shaped displays, Tianma presented a round display with a hole in the middle. Until now, it has been difficult to create comparable shapes because of the matrix-shaped arrangement of the pixel elements required. With individually embedded gate drivers as Virtual Gate Inline Pixel Array (VGIA), the desired degrees of design freedom are achieved when designing the display.

To meet customer demand for free-form displays, Tianma has solved several problems in the manufacturing process. These include the low cutting accuracy and the limited range of shapes that have hitherto precluded any free design options. Laser-assisted material processing offers the possibility of high-precision cuts in the 100 micrometer range. For example, very fine holes can be created by gentle laser ablation. This production technique enables classic and analog clock hands in combination with a background display. Applications include ‘smart’ wristwatches and cockpit instruments in the automotive sector.

A prototype presented by Tianma illustrates the specific features of this technique. The display with a diameter of five inches provides an extremely slim concentric edge of three millimetres. This result is achieved by using a special oxide semiconductor material as active TFT backplane, which offers much higher electron mobility compared to conventional amorphous silicon. Smaller pixel structures, as well as more compact, transparent driver circuits, can be generated while maintaining the same level of current. The latter can be housed in the edge of the screen to save space or even arranged within the active display area.

Despite the capacitive touch sensor (PCAP), the display with a thickness of just 2.1mm can be considered ultra slim. With a resolution of 1080x1080px and a very high contrast ratio of 1,000,000:1, the display is capable of producing impressive graphics.

In addition to customer-specific designs, the manufacturer now offers an increasing number of standardised models. At electronica, Tianma plans to present several new free-form displays for the first time in Europe. Tianma will exhibit in hall B4, stand 231.