To judge the deterioration or a failure condition of LED in a digital signal recording device of movie film speedily to record a sound signal on a movie film steadily in a stable condition.
A shielding plate 18 is provided in a section from positions of S side recording head 9 and P side recording head 11 to S side lens 10 and a P side lens 12 so that light from the S side recording head 9 does not interfere with light from the P side recording head 11 in a digital signal recording device, and one optical sensor 21 is provided in a clearance between the S side lens 10 and the P side lens 12 in such a manner that it comes out equally (1=1) from an end fringe of the shielding plate 18. The optical sensor 21 compares and judges changes of quantity of light from the S side recording head 9 or the P side recording head 11 to judge the deterioration or a failure of a light emitting diode which irradiates light to each recording head 9, 11.
| JPH04284443 | MAGNETIC HEAD |
FUJITA TADAO
KANBE SHUICHI
