Existing research has shown that patent pledging can effectively alleviate financing constraints for small and medium-sized enterprises （SMEs），but the mechanism for obtaining higher loan amounts has not yet been systematically explained. Based on a dual-process framework of signalling theory，this study used patent pledge data from SMEs listed on the NEEQ between 2016 and 2022 as a sample，and empirically tested the relationship between patent originality and pledged financing amounts. The results showed that patent originality has a significant inverted U-shaped effect on pledged financing amounts，meaning that a moderate increase in patent originality can enhance loan amounts by strengthening the observability of signals. However，excessively high originality suppresses the financing effect due to high decoding costs. This non-linear effect is strengthened by two moderators:1） close bank-firm interactions，which lower decoding costs through communication and trust，and 2） board members' external social networks，which improve the bank's value assessment via professional endorsement. Both factors steepen the curve，allowing firms to capture a higher financing premium at optimal originality levels. This study expanded the research on the antecedents of patent pledging and will provide insights for SME patent portfolio management and government policy formulation:moderately increasing patent originality and strengthening communication with financial institutions can help achieve higher pledged financing amounts by balancing innovation value and evaluation costs，thus providing a theoretical basis for overcoming the challenge of "difficulties in realising innovation premiums".