Explanation (of shielding light characteristics of the dark room)
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Explanation
(of shielding light characteristics of the dark room)
(Note 1) What is the first grade of shielding light ability?
It is the method prescribed with the JIS standard L1055-1987.
It is shown that the shielding light characteristics of that material are
more than 99.99%.
A shielding rate is measured in the following method.
JIS L1055-1987 method of shielding light test.
1) The test method. Put test piece between halogen lamp and lux meter.
Then, a shielding rate is measured in the amount of light that it is permeated.
Halogen lamp Wavelength:0.4μm~3μm The main element of the wavelength is a visible area
2) A result is computed in the following.
shielding rate (per cent) = (1-A/B) ×100.
A: lux when test piece is put.
B: lux when test piece isn't put.
A test result is indicated with 99.99%.
(Note2) shielding light characteristic
About the dependence of the wavelength.
We test by using the ultraviolet rays and the laser light in addition to
the JIS standard on us own.
The examination of the ultraviolet rays area (180nm〜400nm).
Cover the detection part of the ultraviolet rays meter with shielding light
curtain. Then, the ultraviolet rays can’t be detected even it is lighted
with the low pressure mercury lamp which has 180nm〜400nm wavelength.
An examination method by the laser light which has the wavelength of 650nm.
Cover the detection part of the power meter (visible light) with shielding
light curtain. Then, input laser light (650nm) in the detection part. It
confirms that the detection power is less than 1nW at this time. This means
that shielding light curtain has more than 99.99% shielding ability .
