1. Field of the Invention
The present invention relates to a light emitting device.
2. Discussion of the Background
In recent years, a display apparatus such as a large size outdoor display has been put to practical use, in which a plurality of light emitting devices, each having one or more light emitting diodes (LED), are arranged in a matrix. In such display apparatuses, due to the surface gloss of the sealing member which seals the surrounding of the light emitting devices, incident outside light such as sunlight and illumination undergoes total internal reflection at the surface of the sealing member, and hence involve problems such as occurrence of indirect glare and poor display contrast.
In an attempt to solve the problems described above, for example, JP 2000-114605A describes an LED indicator which includes a frame-shaped case, an LED substrate disposed in the case, an LED lamp electrically fixed to the LED substrate, and a sealing resin made of a waterproof synthetic resin which is injected in the case to seal the LED substrate and the bottom edge portion of the resin head of the LED lamp. On the surface of the sealing resin, a microscopic irregularity is formed by exposing glass beads so as to reflect incident outside light as scattering light.
JP 2007-234767A describes a frosted protective member which is formed of a resin layer having fillers dispersed therein and has a surface provided with an irregular geometry including depressions and protrusions which enables to reduce surface gloss, and more fillers are distributed below the depressions than below the protrusions. JP 2003-086846A describes a light emitting element which includes a light emitting chip, a first layer covering the light emitting chip, and a second layer having light diffusing members and provided at least on the first layer. The surface of the second layer has a plurality of protrusions in conformity with the shapes of the light diffusing members. JP 2001-077433A describes a light emitting device which includes a semiconductor light emitting element capable of emitting visible light, a light-transmissive mold member covering the semiconductor light emitting element, fluorescent materials contained in the light-transmissive mold member and capable of absorbing visible light from the semiconductor light emitting element and emitting visible light having a longer wavelength than the absorbed visible light, and a light diffusing agent contained in the light-transmissive mold member. The fluorescent materials have a specific gravity larger than that of the light-transmissive mold member and light diffusing agents. JP H10-284759A describes a light emitting device which includes a light emitting element arranged in a package recess, and a mold member arranged over the light emitting element, and diffusing agents for reducing the rate of decrease in the LED luminance than the rate of decrease in the dark luminance are contained in the mold member.
USPTO Backgrounds
USPTO Backgrounds