Patent ID: 6472765
Filing Date: 2002-10-29
Classification: H01L

Abstract:
A plastic encapsulated semiconductor light emitting device comprising a plurality of leads, at least one of which is formed with a dished portion; a semiconductor light emitting element having a central axis in electrical connection across said leads and attached on a bottom surface of said dished portion; a plastic encapsulant for sealing each one end of said leads and said semiconductor light emitting element; and a light-permeating cover removably attached to an outer surface of said plastic encapsulant for enclosing said light emitting element, said cover containing fluorescent particles (16) dispersed therein;said plastic encapsulant comprising a sealing portion formed into a substantially cylindrical shape, and a lens portion formed into a substantially hemispherical shape integral with the sealing portion; said cover comprising a lower portion formed into a substantially cylindrical shape matched to the sealing portion of said plastic encapsulant wherein the lower portion is of substantially uniform thickness, and an upper portion formed into a substantially hemispherical shape integral with said lower portion and matched to the lens portion of said plastic encapsulant; wherein a light irradiated from said semiconductor light emitting element passes through said plastic encapsulant and reaches the fluorescent particles in said cover to activate the fluorescent particles which therefore generate light from said cover with the wavelength different from that of the light from said semiconductor light emitting element; said dished portion has inclined side surfaces for surrounding said bottom surface; the upper portion of said cover is disposed inside of imaginary planes extended from the side surfaces of said dished portion; and said upper portion of said cover has a thickness which is greater than the substantially uniform thickness of said lower portion so that the number of the fluorescent particles in the upper portion of said cover is greater than that in said lower portion, wherein said semiconductor light emitting element device emits a substantially uniform wavelength light through said cover at any angular distance from the central axis thereof.