(iTers News) - As the resolution of TV panels gets as high as 4K UHD, the size of pixels -the very basic elements of a TV picture- is getting smaller and smaller to cram more of pixels into a given space. So do the size of transistors, becoming more susceptible to electric currents leakages, as they scale down in proportion with the pixel size. The smaller and thinner the transistor size is, the more it is susceptible to current leakage. This vulnerability helps explain why LCD display panel makers are looking to Cr , or chromium for transistor gate and S/D electrode  rather than aluminum, or AI.

The shift to Cr is especially gaining speed, as the industry is rapidly rolling out 4K UHD panels. Called after the 4,096 horizontal  lines, the 4K UHD panel incorporates more than 8 million pixels.  

The gate and S/D electrodes are a path for electrons. The Cu electrode boasts a higher electrical conductivity than Al, which means sending signals a lot faster without compromising signal integrity. The technology advantages translate into faster response time and higher brightness.

Leading the shift to Cu gate electrode was LG Display of Korea, according to market research firm IHS Technology. Back in 2006, LG became the world’s first LCD panel maker to start mass-production of Cu gate electrode-based LCD panels. LG is now implementing Cu to produce most of its LCD panels.

Following LG Display’s lead in adopting Cu electrode, Samsung Display Co., AU Optronics Corp., o AUO, Innolux Corporation, Panasonic LCD, and Sharp have also been trying to etch Cu electrodes, but none of those makers did make success until 2010.

In the second half of 2010, Samsung Display, which was then Samsung Electronics Co., started applying Cu electrodes to the mass production lines for the second time in the world. But it experienced a lot of difficulties in the initial stage, so it took time to expand the application, according to IHS. Since 2013, however, SDC has been implementing Cu electrodes to most of its mass production lines. In the beginning, its application rate of Cu electrodes to S/D was extremely low, but recently, the rate has been rising significantly.

After a long development effort, Taiwan's AUO also began to use Cu electrodes to produce LCD panels in 2013 in full scale. As production of UHD panels is gaining momentum, Chinese panel makers are also putting efforts to apply Cu electrodes.

In 2014, Shezhen China Star Optoelectronics Technology Corporation (CSOT) and BOE Technology Group Co. (BOE) already used or plan to use Cu electrodes to produce some of their LCD panels. 

As 4K UHD panel is emerging as a next  grow catalyst,  the adoption of Cu wiring has increased, as major TFT LCD panel makers are turning to Cu wirings. Naturally, it is expected that Cu wirings will be the mainstream in the TFT LCD panel wirings, IHS predicted .