Self-luminescent light source for liquid crystal display watch

A self-luminescent light source for a liquid crystal display watch comprising a layer of fluorescent substance which has a light reflectivity and which contains in association with at least a part thereof radioactive element promethium (.sup.147 Pm), a reflective layer which is disposed on one surface of the fluorescent substance layer and which serves to reflect and scatter fluorescence from the fluorescent substance layer, a case which is disposed on the side of the reflective layer remote from the fluorescent substance layer and which serves to perform shielding from bremsstrahlung ascribable to beta rays given out from the promethium, a first cover which is disposed on the side of the fluorescent substance layer remote from the reflective layer and which serves to absorb the beta rays given out from the promethium and to transmit the light from the fluorescent substance layer, and a second cover, made of a material selected from the group consisting of lead-containing glass and lead-containing acrylic resin, which is disposed on the side of said first cover remote from the fluorescent substance layer and which serves to perform shielding from bremsstrahlung ascribable to the beta rays given out from the promethium and to transmit the light from the fluorescent substance layer, whereby said second cover and said case act as a shielding with respect to bremsstrahlung formed in the light source.