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Abstract

An improved laser markable material useful for encapsulation of electronic devices is obtained by adding TiO.sub.2 or TiO.sub.2 +CrO.sub.3 to common plastic encapsulants formed from a mixture of a resin+filler+carbon black+mold release agent. When irradiated by a laser, the originally grey material turns bright gold, providing a high contrast durable mark. The material has excellent marking contrast as well as better stability with time and temperature as compared to prior art laser markable encapsulants. Desirable concentrations, in weight percent of the compound, are 1-5% TiO.sub.2 and 0-3% CrO.sub.3, with 1-3% TiO.sub.2 and 0.5-2% CrO.sub.3 being preferred. Carbon black is optional but a concentration in the range 0.1-3% by weight is desirable with 0.5-1% preferred. Improved encapsulation and marking methods and improved devices using this material are described.

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First Claim