Topcon BM-9A Luminance Meter

Topcon BM-9A
Luminance Meter

This entry level luminance meter includes the essential features for basic luminance measurements of illuminated surfaces, materials, flat panel displays, and area (extended) light sources.  It is a modular design with a separate detector unit (3 options available) and a base unit (computing & display) allowing you to select the optimal detector for the job.

Suitable for laboratory, production line, or outdoor/field measurements (handheld, battery operation), the BM-9A optical instrument meets a wide range of requirements for the most common light measurement jobs.



Wide luminance range

Measure wide luminance ranges from 0.1 to 2,800,000 cd/m2 (with the 1° detector)


Handheld or tripod measurements

Compact design makes the BM-9A easy to use for handheld or tripod measurements


Three detectors available

Three types of detectors available: 2° / 1° / 0.2°


Luminance measurement of LCDs, CRTs, OLEDs, LEDs, etc.

Transmittance of LCD polarizing plates & filters

Luminance measurement of various light sources

Step it up

If you require lower light measurements (below 0.01 cd/m2), multiple apertures within a single instrument, or color (chromaticity) measurements, consider the Topcon BM-7AC or Topcon BM-5AC. These Color Filter Photometers measure luminance across a broader range with improved speed and precision. Both models make color measurements with dedicated tri-stimulus filters and include four standard measurement apertures: 2° / 1° / 0.2° / 0.1°. The BM-5AC uses a Photo Multiplier Tube (PMT) sensor and is therefore more sensitive than the BM-7AC which uses Silicon Photo Diode sensors.

Parameter Detector
BM-9A20D BM-9A10D BM-9A02D
Measurement Aperture 0.2°
Optical System Objective lens: f=36mm F2.5
Measurement Distance 350mm – Inf.
Luminance Range cd/m2 0.01 ~ 280,000 0.1 ~ 2,800,000 1 ~ 28,000,000
Luminance Accuracy ±2% of reading ± 2 digit
Spot Size at 1m 32.3 mm 16.2 mm 3.23 mm
Min. Spot Size at 35cm 9.5 mm 4.8 mm 0.95 mm
Dimensions Approx 190mm (L) x 108mm (W) x 57mm (H)

Ordering Information

The BM-9A base unit requires at least one detector unit to make measurements. Choose the detector based on your required minimum luminance (sensitivity) and measurement aperture (determines spot size).

Select the BM-9A20D detector if you must measure luminance levels down to 0.01 cd/m2.

Select the BM-9A02D if you require the smallest measurement spot size and can accept the higher minimum luminance level (1 cd/m2).

Select the BM-9A10D for a good mid-range detector which balances spot size and sensitivity.

See the BM-9A Brochure for available options. Popular options include:

  • Keyboard Unit (for entering calibration data or reference measurements)
  • RS-232 cable (for connection to a PC)
  • AC adapter/battery charger
  • AL-13 adapter lens (for reducing the measurement spot).

If you can’t find what you are looking for, contact us for info on Topcon options and accessories.

Want to find out more?

If you are interested in more information, send us an inquiry.