PURPOSE: To obtain a distributed index type flat plate microlens which is brighter than conventional lenses, by dipping the sample glass coated thereon with a mask consisting of two layers of Cr-Au in a molten salt bath, and diffusing thermally and selectively a dopant in the sample glass.
CONSTITUTION: Thin films or Cr 11 and Au 12 are continuously deposited by vacuum evaporation on the surface of sample glass (e.g.; optical glass BK-7). A mask pattern 13 having a prescribed hole diameter is formed on the mask consisting of such thin films, then Au is etched with an I-Ki soln. and Cr with an aq. soln. consisting essentially of KOH, then the resist is stripped. The glass 10 in this state is floated in a molten salt bath 14 consisting of thallium sulfate, zinc sulfate, potassium sulfate and sodium sulfate in gaseous Ar flow, and is brought into reaction at, for example, 574°C. After the glass 10 completed the reaction, the glass is slowly cooled, Au and Cr are successively removed by chemical etching; thereafter, the glass is optically polished, thereby the intended distributed index type flat plate microlens is obtd.
| JP2009210252 | HEAT TREATMENT FURNACE FOR TABULAR MEMBER |
OKAMOTO NORIHISA
ITOU NAOYUKI
Next Patent: JPS5950051