In optical maskless lithography in concern, a digital micromirror device plays the role of a digital mask. Due to the spatial/temporal configuration of micromirror arrays/response or the specification of illumination/projection optics, the irradiance may be influenced by diffraction effects. In present study, an investigation of various optical maskless lithography models based on binary micromirror reflections is performed in consideration of the diffraction effect. To evaluate lithographic parameters dissolved in the lithography models, parametric studies are performed focusing on pattern fidelity and line edge roughness. To reduce corner rounding phenomena due to an image size and further to a reflection criterion, the auxiliary corner reflection adjusting feature (ACRAF) analogous to conventional serif are employed and the effectiveness of ACRAFs is analyzed. The potential of utilizing the adjusted parameters for enhancing pattern fidelity and line edge roughness under diffraction effects is demonstrated through simulations and experiments.