The results show that the pencil hardness of the laminated structure depends strongly on OCA thickness and also that the position of thick OCA affects the hardness. In particular, the thickness of the upper OCA has a larger impact than the thickness of the lower OCA but the impact of OCA3, which is far away from surface, still cannot be ignored. We also investigated the effect of changing the shear modulus of OCA and, as shown in Figure 2, it was found that the OCA shear modulus is also important in determining pencil hardness. These results suggest that using as thin and high modulus OCA as possible is effective, as is reducing the number of OCA layers by combining more than one functional films such as using coating polarizer or on-cell type touch panel.