Patent ID: 8344311

Claim:
An optical touch panel, comprising: a transparent plate; a plurality of light-emitting devices and a plurality of light-receiving devices arranged in the vicinity of the transparent plate; and a substrate to which at least one of the plurality of light-receiving devices is fixed, wherein a plurality of light paths are formed in front of the transparent plate, each light path being formed by a pair of one of the plurality of light-emitting devices and a corresponding one of the plurality of light-receiving devices, the substrate has a surface layer that has a surface roughness which causes diffuse reflection of the same kind of light as light emitted by each of the plurality of light-emitting devices, and a region, referred to as a diffuse-reflection region hereinafter, having the surface roughness on a surface of the surface layer includes at least a region on the surface of the surface layer included in a directivity range of said at least one of the plurality of light-receiving devices fixed to the substrate.