Patent ID: 6891530

Claim:
A touch panel-including illuminator comprising: a light pipe made of a transparent plate-like material having an upper surface, a lower surface and at least one incidence side surface, said upper surface being provided with light output means through which light incident on said incidence side surface is made to emerge from said lower surface; a light source disposed on said incidence side surface of said light pipe; a transparent adhesive layer; and a transparent touch panel including an input position detecting mechanism and bonded to an outer side of said upper surface of said light pipe through said transparent adhesive layer; wherein said light output means are constituted by fine grooves which are disposed discontinuously, each of which is made of a concave portion having a length of not larger than 250 μm and a depth of not larger than 50 μm and not larger than ⅕ as large as the length, and each of which is shaped like an approximate triangle in section; wherein each of said fine grooves has an optical path changing slope inclined at an angle ranging from 35 to 48 degrees to said lower surface of said light pipe, and a steep slope inclined at an angle of not lower than 60 degrees to said lower surface of said light pipe so as to face said optical path changing slope; and wherein said fine grooves are disposed so that said optical path changing slopes face said light source so as to be able to receive light incident on said incidence side surface of said light pipe from said light source.