Abstract: A light-emitting element includes: a phosphor layer including phosphor (phosphor particles) of at least one type; a substrate which has a thermal conductivity higher than a thermal conductivity of the phosphor layer, the substrate having a principal surface above which the phosphor layer is disposed; and a joining part which is interposed between the phosphor layer and the substrate to join the phosphor layer and the substrate together with metal. An adhesion layer and a reflecting layer are interposed between the joining part and the phosphor layer, the adhesion layer being light-transmissive and on a principal surface of the phosphor layer which faces the substrate, the reflecting layer being on a principal surface of the adhesion layer which faces the substrate.

Abstract: A photoelectric smoke detector has a circuit substrate coupled to an optical-system base as disposed in a circuit accommodating zone defined within a detector housing by the base together with a smoke supervisory zone, a light projecting element and an integrated circuit incorporating therein a light receiving element and smoke detecting means are mounted to the circuit substrate, and the optical-system base holds therein a light receiving lens which is capable of condensing scattered light from smoke particles onto the light receiving element in the integrated circuit on the circuit substrate. Effective reduction in the number of constituent parts is thereby attained, to promote reduction in manufacturing costs, and to effectively realize dimensional minimization.

Abstract: A sensor in IC formation has a light emitting means, and a light receiving means disposed for receiving a faint pulsed light generated by scattering of light emitted from the light emitting means, in which a switching means capable of short-circuiting between sensor circuit lines is provided for being triggered by a counter means operated in response to an output from the light receiving means, and constituent elements of respective components of the sensor including the said means and capable of being formed in the IC are formed as integrated circuits on a dielectric isolation substrate, whereby electric isolation of the respective elements can be made complete irrespective of light irradiation to realize effective interelement junction and isolation.