Infocomm 2017 saw us debut a new driver chip which is the latest innovation, resulting from 3 years of development from the SiliconCore research team.
ZACH stands for Z(Impedance) Adjustment for Color Homogeneity, giving our displays market leading dynamic range and color reproduction.
The LED driver issue
Current LED displays have difficulty in achieving low brightness uniformity. LED has two natural characteristics that can make LED displays far superior than any other display technology, one is high energy efficiency and the other is fast response time. Its only downfall is this non-uniformity due to passive impedance variation in each LED diode within the PCB. This is caused by individual LED being manufactured differently with varying capacitance and turn-on voltage. To magnify the problem, each LED is mounted in a different position on the PCB which means the trace between each LED to LED driver is also not the same.
This problem gets worse with higher resolution displays, where it affects the grey scale performance. For example with 1.2mm or 0.95mm pixel pitch, running 16 bit grey scale at 60Hz frame rate with 16 scan structure, the minimum light pulse is 15 nanoseconds and the current level can be less than 1mA. Such a small current pulse may not be able to travel through the vastly different impedance network on the PCB and to the LED itself. This non-uniformity can be observed at any low brightness spot on the screen in any color. In most LED displays, it is common practice to avoid the non-uniformity issue by raising the minimum brightness level and increasing the current pulse width or level. All these methods result in a lower greyscale performance and distort the original picture quality. This in turn compromises the dynamic range of the screen in order to obtain uniformity. This has been a particular issue in high fidelity video or simulation applications such as movie theatres and military simulators.
ZACH Driver Chip to the rescue
SiliconCore has long recognized this problem and has allocated major R&D resource into solving it.
The ZACH driver chip uses active circuit to compensate passive impedance variation on each individual LED. A smart sensing circuit embedded in LED driver is capable of detecting impedance variation of each LED diode driven from LED driver, creating a unique feedback loop to record the impedance variation of the entire panel, providing a unique active compensated pulse width adjustment.
This achieves uniform brightness and homogenous color at especially low brightness levels.
Z.A.C.H . enables SiliconCore displays, already the brightest in the industry, to also provide accurate color reproduction in the areas of low brightness. This is most evident in pictures with shadows and areas of greatest contrast from light to dark. Combined with SiliconCore’s low power Common Cathode Technology (CCT), a 4K screen can achieve uniform maximum brightness of over 1,800Nits and minimum brightness under 0.1Nits, which is almost a 50 fold increase on any other screen. The effective dynamic range is over 18,000 to 1 or over 14 bits. Reproduction of color can be achieved beyond rec 2020 color bit depth, which is fast becoming the industry standard.
The result – shipping now!
This new chip is a breakthrough for LED displays, producing a fully immersive picture quality for simulation and highly detailed image applications. SiliconCore’s electronic design team has integrated all these technologies into an LED driver design which preserves these natural characteristics, resulting in energy efficiency, rapid response time and being able to maintain incredible color over a long lifetime.
SiliconCore displays, Lavender 1.2mm, Magnolia 1.5mm and Camellia 0.95mm are already shipping with the new Z.A.C.H. LED. This technology is ideal for cinema, command and control, and simulation environments thanks to the incredible dynamic range and color fidelity of the display. Corporate and retail clients will notice a difference in areas of greatest contrast.