Abstract: Disclosed is a semiconductor laser device comprising a layered semiconductor region capable of laser oscillation and including at least an optical confinement region consisting of stacked semiconductor layers, means for injecting current into the optical confinement region, and means for constructing an optical resonator; switching means for supplying the layered semiconductor region capable of laser oscillation with a current having a value near a threshold current value for the laser oscillation; and switching means for feeding a current to be superposed on the current supplied to the layered semiconductor region capable of laser oscillation, this switching means being capable of controlling the current to be superposed through an external input thereof.

Abstract: A semiconductor laser light emitting element comprises a semiconductor substrate, a laminate region of semiconductor layers having at least a first, a second and a third semiconductor layer formed over the substrate and having a p-n junction defined therein. The first and third semiconductor layers have smaller refractive indices and greater forbidden band gaps than the second semiconductor layer and are opposite in conductivity type to each other. Provided are on the substrate a field effect transistor section having first and second electrodes and a gate electrode disposed between the first and second electrodes, a means for serving as an optical resonator for emitting light in the lengthwise direction of the p-n junction.

Abstract: A light emitting device wherein a blue screen or a red screen is excited by 5 to 25eV photons or electrons, the blue screen containing a self-activated phosphor which is represented by the general formula MP.sub.b V.sub.1-b O.sub.4 where M stands for at least one member selected from the group consisting of yttrium (Y), scandium (Sc), rare-earth elements having atomic numbers of 57-62 and 64-71, and group-IIIb elements of the periodic table, and where O<b<1.0, the red screen containing a trivalent europium (Eu.sup.3+) activated phosphor which is represented by the general formula M.sub.1-a Eu.sub.a P.sub.b V.sub.1-b O.sub.4 where M stands for at least one member selected from the group consisting of yttrium (Y), scandium (Sc), rare-earth elements having atomic numbers of 57-62 and 64-71, and group-IIIb elements of the periodic table, and where O<a<1.0 and 0<b.ltoreq.1.0.

Abstract: A light emitting device wherein a blue screen or a red screen is excited by 5 to 25eV photons or electrons, the blue screen containing a self-activated phosphor which is represented by the general formula MP.sub.b V.sub.1-b O.sub.4 where M stands for at least one member selected from the group consisting of yttrium (Y), scandium (Sc), rare-earth elements having atomic numbers of 57 - 62 and 64 - 71, and group-IIIb elements of the periodic table, and where 0 <b<1.0, the red screen containing a trivalent europium (Eu.sup.3+) activated phosphor which is represented by the general formula M.sub.1-a Eu.sub.a P.sub.b V.sub.1-b O.sub.4 where M stands for at least one member selected from the group consisting of yttrium (Y), scandium (Sc), rare-earth elements having atomic numbers of 57 - 62 and 64 - 71, and group-IIIb elements of the periodic table, and where 0<a <1.0 and 0<b.ltoreq.1.0.

Abstract: A radiographic phosphor screen to be used as an intensifying screen, a direct viewing fluorescent screen, an input screen of an image intensifier tube for radiography and the like, which comprises a substrate and, supported thereon, a phosphor represented by the following general formula:M(P.sub.x, V.sub.1.sub.-x)0.sub.4wherein M stands for at least one element selected from the group consisting of yttrium (Y), lanthanum (La), gadolium (Gd) and lutetium (Lu) and x is a number of from 0.7 to 0.99,Or a phosphate formed by activating said phosphor with 0.01 to 0.5 mole % of thulium (Tm).