21.3: An Improved Dynamic Ratio Less Shift Register Circuit Suitable for LTPS‐TFT LCD Panels

We have improved the dynamic ratio less shift register circuit, originally designed for use in Si-LSIs, so as to be applied to LTPS TFTs on the glass substrate with stable operations. In the operation of the dynamic circuit, the conditions arising from two major obstacles, drain avalanche hot carrier effect and massive bias current, which degrade the transistors in the long term operation, can be avoided. By adopting this improved circuit, we are successfully mass-producing highly reliable LTPS-TFT LCD panels which consist only of n- type TFTs.