A document photosensor is provided which comprises a substrate 11, 12, a bracket 41, 42 disposed on substrate 11, 12 for forming a light diffusion chamber 53 and a light receiving chamber 58 separated from each other, an LED chip 21, 31 surface-mounted on substrate 11, 12 in light diffusion chamber 53, and a PD chip 37, 38 surface-mounted on substrate 11, 12 in light receiving chamber 58. At least one of the backing sheet or cover sheet has a transparent portion in alignment with the dry indicating composition, and wherein the cover sheet may be peeled from the backing sheet and resealed. The material joint is realized by a liquid metal. If the contact information is successfully retrieved, then the user may be routed to the foreign network.