Topcon BM-7AC - Measurement Operation; Example of Use; Measuring a Light Source Having Directivity; Measuring a Minute Surface

2. Measurement Operation
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2. Measurement Operation
2.1 Example of use
An example of measurement will be given here. Use it as a reference when using this instrument.
2.1.1 Measuring a Light Source Having Directivity
When observing a light source with high directivity such as an LED or an uneven light source, it
may not be possible to obtain data having good reproducibility. In that case, perform
measurement using a white board as shown below.
2.1.2 Measuring a Minute Surface
When measuring a minute sample that is smaller than the measurement diameter of the BM-7AC,
use an optional attachment lens. There are two types of attachment lenses, AL-6 and AL-11.
BM-7AC Measurement Diameter
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「Appendix: Specifications」
The attachment lens is mounted using the screw on the tip end of the BM-7AC objective lens.
Also, when using the attachment lens, a correction factor must be set for the BM-7AC unit.
Correction Factor Setting
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「3.6 Correction Factor」
The luminance measurement diameter changes depending on the measurement angle.
AL-6
Measurement Angle
Measurement diameter (mm)
2°
1.98 ～ 2.75
1°
0.99 ～ 1.37
0.2°
0.20 ～ 0.27
0.1°
0.10 ～ 0.13
* Measurement distance 52 to 67 ㎜ (From the tip end of the frame)
AL-11
Measurement Angle
Measurement diameter (mm)
2°
1.22 ～ 1.49
1°
0.61 ～ 0.74
0.2°
0.12 ～ 0.15
0.1°
0.06 ～ 0.07
* Measurement distance 20.4 to 24.8 ㎜ (From the tip end of the frame)
Light
Source
White Board
BM-7AC
Luminance = Measurement
value L x Luminance factor