Liquid-Crystal-on-Silicon (LCoS) microdisplays input RGB data, while most video decoders adapt video signals to digital YCbCr format. As a result, a color space converter which changes YCbCr signals to RGB format is required to interface the microdisplay with video images. In this research, the proposed implementation of color space converter was integrated into the LCoS microdisplay. This integration could reduce the system complexity, power consumption and cost in comparison with the discrete implementation, and it also maintained the same overall size of the microdisplay panel....[ Read more ]

Liquid-Crystal-on-Silicon (LCoS) microdisplays input RGB data, while most video decoders adapt video signals to digital YCbCr format. As a result, a color space converter which changes YCbCr signals to RGB format is required to interface the microdisplay with video images. In this research, the proposed implementation of color space converter was integrated into the LCoS microdisplay. This integration could reduce the system complexity, power consumption and cost in comparison with the discrete implementation, and it also maintained the same overall size of the microdisplay panel.

The carry-save multiplier architecture was chosen to design the color space conversion. Different approaches minimizing equivalent gate count and delay were explored. The errors of 8-bit and 6-bit optimized conversion designs were found out to be 0.4% and 3% respectively by the Matlab. The designs were implemented by the Field Programmable Gate Array (FPGA). The total equivalent gate counts of 8-bit and 6-bit conversions were synthesized to be 1740 and 1050 respectively. The whole circuit was applied to fabricate the multiple-standard color space converter IC chip using 0.6um CMOS process. The Complex Programmable Logic Device (CPLD) was introduced to generate test vectors to the fabricated chips. The converted results of different standards and output combinations were feedback to the CPLD for comparisons. The functionality was also verified by converting the video signals from the video decoder and giving correct images in the microdisplay panel. The proposed color space converter was integrated into the LCoS microdisplay of 432 x 240 resolution. The layout with 1.8 x 0.7 mm² area was adapted to 0.35um CMOS process. The timings were determined in post layout simulations. The color space converter, integrated into the silicon microdisplay, performed the conversion with maximum operating frequency up to 54 MHz.