| 摘要 |
<p>PURPOSE:To attain highly accurate measurement of light shield effect by loading a tape to a cassette container whose both ends have a light passing hole and whose inside is dark in measuring the light shield effect of a cassette tape and making a diffused light incident on the light passing hole and receiving the transmitted light by a photodetector. CONSTITUTION:The tape cassette container 15 whose inside is dark and whose both ends have the light passing holes 7L, 7R is provided to the bottom of a case 100 and a tape cassette 1 to measure the light shield effect is contained therein. Moreover, the container 15 is provided with a light source container 21 whose lower face has a diffusion glass 31, a light source 16 is fitted on the ceiling, the light therefrom is diffused by the glass 31 and transmitted through the tape 1 via the holes 7L, 7R. Then the transmitted light is made respectively incident in the photodetectors 17L, 17R, the output is fed to a light shield effect detection means 18 being an electric system unit to detect the light shield effect. Thus, the diffused glass is used to uniformize the distribution of illuminance.</p> |
