264results about How to "Good color properties" patented technology

To provide a phosphor containing a comparatively much red component and having high light emitting efficiency, high brightness and further high durability, the nitride phosphor is represented by the general formula LXMYN((2 / 3)X+(4 / 3)Y):R or LXMYOZN((2 / 3)X+(4 / 3)Y−(2 / 3)Z):R (wherein L is at least one or more selected from the Group II Elements consisting of Mg, Ca, Sr, Ba and Zn, M is at least one or more selected from the Group IV Elements in which Si is essential among C, Si and Ge, and R is at least one or more selected from the rare earth elements in which Eu is essential among Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er and Lu.); contains the another elements.

A light emitting device includes a first unit having a first excitation light source including a laser element emitting blue wavelength band excitation light, and a first wavelength converting member including at least one type of fluorescent material and which absorbs at least a portion of a first excitation light, converts the wavelength, and releases light with a wavelength longer than the first excitation light, and a second unit having a second excitation light source including a laser element which emits excitation light with a wavelength band shorter than the blue wavelength band excitation light, and a second wavelength converting member which includes at least one type of fluorescent material and which absorbs at least a portion of a second excitation light, converts the wavelength, and releases light with a wavelength longer than the second excitation light. The first unit and the second unit are combined using a bundle fiber.

A medical lighting apparatus includes single or plural LED units. Each of the LED units comprises a plurality of concave reflecting surfaces and an LED element disposed in front of each of the reflecting surface so as to radiate light toward each of the reflecting surfaces. Each of the LED units is arranged so that the lights radiated from its LED elements are reflected by the reflecting surfaces, emerge outside and are superimposed on one another on an area to be illuminated, respectively, while illuminating the area. The LED elements of each of the LED units comprise a combination of different emitting colors so as to enhance the color rendering properties.

A semiconductor light emitting device is composed of a blue light emitting diode, a red light emitting layer grown epitaxially on the blue light emitting diode, and an insulating material containing a YAG fluorescent material. The red light emitting layer is made of, e.g., undoped In0.4Ga0.6N having a forbidden band width of 1.9 eV and formed on a p-type semiconductor layer to have a configuration consisting of a plurality of mutually spaced-apart islands.

A light emitting device is provided that has a semiconductor light emitting element and a phosphor which converts a part of the luminescence spectrum emitted from the semiconductor light emitting element. The luminescence spectrum of the semiconductor light emitting element is located between a near ultraviolet region and a short-wavelength visible region, and the phosphor is made by adding a red luminescent activator to a base material of a blue luminescent phosphor. Thereby, improving the color shading generated by the dispersion of the spectra of the light emitting elements and obtaining the light emitting device having a high brightness and a good color rendering properties. With the light emitting device, it is possible to provide the light sources for the lighting apparatus of medical treatments, the flash plate of a copying machine, etc., in which a good color rendering property is required.

A phosphor having an excitation band relative to lights in the wide range of wavelengths from ultraviolet to visible light, and having an emission spectrum in the red range and so on, with a wide half value width, and an LED and a light source using the phosphor and emitting white and other color lights with good color rendering properties are provided. Powdered raw materials of Ca3N2 (2N), CaO (2N), AlN (3N), Si3N4 (3N), and Eu2O3 (3N) are prepared, and the respective raw materials are mixed to have a mole ratio of the respective elements of Ca:Al:Si:Eu=0.985:1:1:0.015. The mixed raw materials are fired at 1000° C. or higher in an inert atmosphere for three hours, and thereafter pulverized to obtain a phosphor having a composition of CaAlSiN2.83O0.25:Eu, which is one example of the phosphor satisfying the above described object. Furthermore, by combining the phosphor with an appropriate LED or a light source emitting from ultraviolet light to visible light, the LED and the light source emitting white and other color lights with good color rendering properties can be obtained.