Shielding coat membrane for discharge lamp and manufacturing process thereof
AssigneeMatsushita Electric Industrial Co., Ltd.
InventorsTatsuo Mifune, Masaru Ikeda
Life of this patent
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Abstract
A conventional black oxide colorant used for the shielding coat membrane of the D2R type discharge lamps for automobiles has a problem that its wettablity with the granulated glass is not good so that a strong membrane is difficult to be obtained. A paint for the shielding coat membrane comprises polycrystalline silica and Mn-doped ferric oxide as a black colorant, which has a good wettability with the granulated glass and a shielding characteristics so as to improve the membrane strength, thereby providing a lamp with the shielding coat membrane that passes all evaluation test in the view point of the membrane strength, the light transmissivity, the discoloration, the suppression of pealing-off and cracking.
Claims15
A paint for a shielding coat membrane for a discharge lamp comprising polycrystalline silica and Mn-doped ferric oxide, and a granulated glass mostly made of silica, wherein solid components in said paint include 5-20 wt % granulated glass and 80-95 wt % of a mixture of 20-80 wt % polycrystalline silica and 20-80 wt % Mn-doped ferric oxide.
A lamp comprising a shielding coat membrane formed on a surface of said lamp by painting a paint thereon, said paint including polycrystalline silica, Mn-doped ferric oxide, and a granulated glass mostly made of silica.
A process for manufacturing a lamp comprising:
- painting a paint including polycrystalline silica, Mn-doped ferric oxide, and a granulated glass mostly made of silica, on a surface of said lamp;
- and
- sintering said lamp so as to form a shielding coat membrane.
Dependencies are inferred from the claim text.