| 摘要 |
PROBLEM TO BE SOLVED: To realize a polarizer with excellent characteristics which has large double refraction, no optical rotatory power and little crystal defect and which is chemically stable by using a lithium tetraborate single crystal as a polarizer to polarize UV rays. SOLUTION: A lithium tetraborate single crystal is used as a polarizer to polarize UV rays. The polarizer of the purpose is a precise polarizer with good reproducibility in which optical inhomogeneity such as deformed interference fringes in a conoscope image can not be observed. Further, the polarizer is excellent with a high extinction ratio. In the production of the polarizer from a lithium tetraborate single crystal by a Czochralski method, the temp, gradient in the atmosphere between the surface of the fused liquid and 1-cm height above the liquid is specified to 30 deg.C/cm to 200 deg.C/cm, and the temp. gradient in the upper atmosphere is specified to 10 deg.C/cm to 50 deg.C/cm. The drawing speed is specified to 0.1 mm/hour to 2 mm/hour. By this method, the polarizer with little crystal defect can be easily mass-produced.
|
