|Activities:||Idea, proof of concept, design electronics and firmware, prototyping, chip-on-glass|
|Technologies:||STM32 Cortex M4, SPI, DipTrace, C, USB, USB-MSC, EcFAT, solar power, COG|
This project is about the development of a monochrome reflective display system. Although quite similar to the preceding CMY display project, the focus is now on emphasis of the low-power nature of the technology.
The display elements of this technology consists of small 7x11-pixel 'tiles'. These tiles fit together to form a larger display element. Because of this modular approach, we have come up with a solution to add the necessary electronics on the back of each tile. Next these tiles are interconnected by a serial pixel bus and power distribution.
Being just a black&white display, the driving circuitry is much simpler than the 256-level PWM driving on the CMY display. Because of this, the tile-driver electronics is basically a single chip solution using a 80-channel high voltage driver with SPI-bus data interface.
Initial bi-panes had all their pixels connected via a couple of wide flat-flex cables. Handy for have direct access to pixel signals and to experiment with different solutions for driving them. However, not so great for production and robustness. Therefore we suggested the use of chip-on-glass drivers and assisted in the development of this solution.
One of the lead customers on this ECCB technology, a manufacturer of outdoor LED screens, has asked us to develop the interfacing between this new technology and their existing LED controllers. This gave them a quick start on experimenting and testing with these reflective screens.