Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – At least one aryl ring which is part of a fused or bridged...
Patent
1994-12-09
1997-04-08
Yoon, Tae
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
At least one aryl ring which is part of a fused or bridged...
524265, 524431, 523205, 523212, 252582, 252584, C08K 322, G02B 520
Patent
active
056188722
DESCRIPTION:
BRIEF SUMMARY
The invention relates to inorganic fillers and organic matrix materials with refractive index adaptation. Organic materials in which inorganic fillers are incorporated appear in many industrial uses. In these cases, the inorganic fillers often not only have a replacement and dilution function, but serve to modify the organic matrix material or impart to these initially certain properties. In many cases, especially if optical phenomena or effects play a role during application or use, use-specific adaptation of the optical refractive indices of filler and matrix material is desirable or even necessary.
For example, in the case of optical, electro-optical and optoelectronic components, such as, for example, light-emitting diodes and laser diodes, optocouplers and photodetectors, the semiconductor structural elements are enclosed by embedding compositions based on polymeric or polymerizable systems, the embedding compositions having to fulfill optical functions.
Because of the optical properties of the fillers employed to date, such as, for example, calcium fluoride, calcium carbonate, barium sulfate, amorphous silicic acid and the like, the amount of these employed is, however, currently limited. About 25% by weight is to be regarded as a still tolerable upper limit for the customary fillers. This lies in the fact that due to the different refractive indices of the inorganic filler and polymer matrix, the embedding composition becomes optically more inhomogeneous as the content of filler increases, and a considerable loss of scattered light occurs due to light scattering on the inorganic particles. The refractive index of the usual epoxy resin systems which are customary as embedding compositions for optical, electro-optical and optoelectronic components is about 1.5, that of calcium fluoride is 1.43 and that of spheroid particles of amorphous silicic acid is 1.42.
Other optical inhomogeneities, which sometimes cause even greater optical losses, arise from the fact that the inorganic particles usually employed tend to agglomerate, cannot be dispersed sufficiently uniformly in the casting resin and tend to undergo sedimentation in the non-cured state. Highly transparent embedding compositions which are free from scattered light are essential for uses such as in laser diodes and optocouplers.
The state of affairs is somewhat different in the case of light-emitting diodes for display purposes. These should have an intensive scattered light cone with a spatially uniform distribution of intensity coupled with a minimum intrinsic absorption of the embedding composition in the spectral range of the light-emitting diode emission. For this purpose, diffuser materials which are intended to ensure adequate light scattering are incorporated into the casting resin systems which function as embedding compositions. The diffuser materials employed are usually the inorganic fillers already mentioned, such as calcium fluoride, calcium carbonate, barium sulfate and amorphous silicic acid. The scattered light yield depends on the amount of particles added and their refractive index, particle shape, particle size and particle size distribution. The greatest possible difference between the refractive indices of the particle material and the polymer matrix material and particles which are as spherical as possible and have a narrow particle size distribution are favorable. However, the inorganic fillers usually employed as diffuser materials as a rule have non-uniform particle shapes and a relatively wide particle size distribution which is not constant from batch to batch. This leads to variations in the scattering properties of the light-emitting diodes and losses in the light yield. Inadequate dispersion properties and sedimentation of the particles in the resin system also cause such adverse effects.
There was therefore a need for improved inorganic fillers for use in polymeric or polymerizable systems, in particular in embedding compositions for optical, electro-optical and optoelectronic components.
It has now been found that
REFERENCES:
patent: 2304754 (1942-12-01), Wainer
patent: 5008305 (1991-04-01), Kennan et al.
patent: 5045574 (1991-09-01), Kawata et al.
patent: 5153251 (1992-10-01), Lupinski et al.
patent: 5189902 (1993-03-01), Groeninger
patent: 5190698 (1993-03-01), Coltrain et al.
patent: 5270353 (1993-12-01), Nakano et al.
patent: 5278204 (1994-01-01), Tojo et al.
patent: 5478878 (1995-12-01), Nagaoka et al.
Marquard Kurt
Pohl Ludwig
Reeh Ulrike
Waitl G unter
Wipfelder Ernst
Merck Patent Gesellschaft mit beschrankter Haftung
Siemens AG
Yoon Tae
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