Abstract: It is an object of the present invention to provide an infra-red light emitting phosphor having an excellent chemical stability and desirable light emitting properties. The infra-red light emitting phosphor is represented by a chemical formula: (A1-x-yNdxYby)VO4, wherein A represents at least one element selected from yttrium (Y), gadolinium (Gd), lutetium (Lu) and lanthanum (La); x and y respectively satisfy the requirements: 0.01?x?0.3 and 0.01?y?0.4, provided that (x+y)?0.5 and 0.2?(y/x)?6. This vanadate phosphor having the constitution described above can act as an infra-red light emitting phosphor having an excellent chemical stability and desirable light emitting properties.

Abstract: A semiconductor light-emitting device has a semiconductor light-emitting element for emitting light with emission wavelengths of 390 to 420 nm, wherein the wavelengths of light from the semiconductor light-emitting element are converted by a fluorescent substance having a monochromatic emission peak. The emission wavelengths of 390 to 420 nm, which have almost no adverse effect on human bodies and components of the semiconductor light-emitting device, are in a low human visibility range. Since light whose wavelengths are converted by the fluorescent substance are hardly affected by direct light from the semiconductor light-emitting element, light from the fluorescent substance has a favorable color tone. Also, the semiconductor light-emitting device allows desired luminous colors to be obtained only by changing fluorescent substance materials without changing the structure of the semiconductor light-emitting device or the semiconductor light-emitting element.

Abstract: It is an object of the present invention to provide an infra-red light emitting phosphor having an excellent chemical stability and desirable light emitting properties. The infra-red light emitting phosphor is represented by a chemical formula: (A1-x-yNdxYby)VO4, wherein A represents at least one element selected from yttrium (Y), gadolinium (Gd), lutetium (Lu) and lanthanum (La); x and y respectively satisfy the requirements: 0.01?x?0.3 and 0.01?y?0.4, provided that (x+y)?0.5 and 0.2?(y/x)?6. This vanadate phosphor having the constitution described above can act as an infra-red light emitting phosphor having an excellent chemical stability and desirable light emitting properties.

Abstract: A semiconductor light-emitting device has a semiconductor light-emitting element for emitting light with emission wavelengths of 390 to 420 nm, wherein the wavelengths of light from the semiconductor light-emitting element are converted by a fluorescent substance having a monochromatic emission peak. The emission wavelengths of 390 to 420 nm, which have almost no adverse effect on human bodies and components of the semiconductor light-emitting device, are in a low human visibility range. Since light whose wavelengths are converted by the fluorescent substance are hardly affected by direct light from the semiconductor light-emitting element, light from the fluorescent substance has a favorable color tone. Also, the semiconductor light-emitting device allows desired luminous colors to be obtained only by changing fluorescent substance materials without changing the structure of the semiconductor light-emitting device or the semiconductor light-emitting element.

Abstract: A semiconductor light-emitting device has a semiconductor light-emitting element for emitting light with emission wavelengths of 390 to 420 nm, wherein the wavelengths of light from the semiconductor light-emitting element are converted by a fluorescent substance having a monochromatic emission peak. The emission wavelengths of 390 to 420 nm, which have almost no adverse effect on human bodies and components of the semiconductor light-emitting device, are in a low human visibility range. Since light whose wavelengths are converted by the fluorescent substance are hardly affected by direct light from the semiconductor light-emitting element, light from the fluorescent substance has a favorable color tone. Also, the semiconductor light-emitting device allows desired luminous colors to be obtained only by changing fluorescent substance materials without changing the structure of the semiconductor light-emitting device or the semiconductor light-emitting element.

Abstract: A semiconductor light-emitting device has a semiconductor light-emitting element for emitting light with emission wavelengths of 390 to 420 nm, wherein the wavelengths of light from the semiconductor light-emitting element are converted by a fluorescent substance having a monochromatic emission peak. The emission wavelengths of 390 to 420 nm, which have almost no adverse effect on human bodies and components of the semiconductor light-emitting device, are in a low human visibility range. Since light whose wavelengths are converted by the fluorescent substance are hardly affected by direct light from the semiconductor light-emitting element, light from the fluorescent substance has a favorable color tone. Also, the semiconductor light-emitting device allows desired luminous colors to be obtained only by changing fluorescent substance materials without changing the structure of the semiconductor light-emitting device or the semiconductor light-emitting element.

Abstract: An information reading method includes the steps of irradiating a phosphor activated by neodymium and ytterbium ions with exciting light of a wavelength between 500 nm and 780 nm that can excite the neodymium ions, and reading the information by receiving the light emitted from the phosphor with a photodetector designed to detect light with wavelengths between 840 m and 1100 nm. Consequently, the information recorded using the phosphor activated by neodymium and ytterbium ions can be read with a high performance without using a filter for cutting the exciting light.