| 摘要 |
PURPOSE:To decrease the change in spectroscopic transmission resulted from the change in temperature and enhance the precision in measurement by using a single layer film optical filter as at least one filter of a reference light and a measuring light narrow zone filters. CONSTITUTION:A signal layer film optical filter SL by an evaporation method with respect to other surface of a substrate SUB by means of one material of materials constituting a multi-layer film ML. The temperature characteristics of spectroscopic transmission of a single layer film SL has the same porality as that of the multi- layer film ML and by adjusting the film thickness thereof, a desired characteristic can be obtained. Thus, of the filters for the reference light and measuring light, at least one filter constituting this single layer film optical filter SL can prevent the precision deterioration due to the change in temperature. |
