Light Transmission Meter
Light Transmittance Meter
Multi-Wavelength Light Transmission Meter
Advanced Light Transmittance Meter
ASTM D1003 ASTM D1494-17 ASTM D1746-15
ISO 9050:1990 ISO 13468-1:2019

Handheld Multi-Wavelength Luminous Transmission Meter - Test Procedure:

The Handheld Light Transmission & Opacity Meter QPI‑115 is designed for rapid, quantitative measurement of optical transmission and opacity across multiple spectral ranges - UV (Ultraviolet), VL (Visible Light) and IR (Infrared). Its modular sensor system and digital calibration architecture allow accurate field or laboratory evaluation of transparent, translucent, and coated materials.

1. Instrument Preparation

1. Power‑On and Initialization

   • Press the power key to activate the meter.

   • The display performs a self‑check, confirming sensor connectivity and battery voltage.

   • The firmware automatically loads the last calibration profile.

2. Sensor Selection

   • Connect the required optical sensor via the standard interface cable:

     • UV Sensor: 350 nm range for ultraviolet transmission.

     • VL Sensor: 400–750 nm range for visible light transmission.

     • IR Sensor: 850–950 nm range for infrared transmission.

   • The instrument automatically recognizes the sensor type and adjusts internal gain and wavelength compensation.

3. Automatic Calibration

   • Place the sensor in the supplied calibration cradle or against a certified opaque reference plate.

   • Press CAL to perform zeroing.

   • The display confirms calibration with a “0.0 % Transmission” reading.

2. Sample Preparation

1. Surface Cleaning Ensure the sample surface is free of dust, fingerprints, or coatings that could scatter light.

2. Sample Positioning

   • Place the sample between the emission window and sensor aperture.

   • Maintain full contact without air gaps.

   • For curved or flexible samples, use the optional alignment fixture to ensure consistent geometry.

3. Environmental Conditions

   • Ambient light should be minimized to prevent stray illumination.

   • Recommended temperature range: 20 - 25 °C for stable readings.

3. Measurement Procedure

1. Select Measurement Mode

   • Transmission Mode: Measures percentage of incident light passing through the sample.

   • Opacity Mode: Inverse ratio of transmitted light relative to a reference blank.

2. Initiate Measurement

   • Press Measurement

   • The meter emits a controlled light pulse from the internal LED source.

   • The sensor detects the transmitted intensity and converts it to a digital signal.

3. Data Processing

   • The microcontroller applies wavelength‑specific correction factors and temperature compensation.

   • Transmission and opacity values are displayed in real time as % T and % O.

   • Optional averaging mode computes mean values over multiple readings.

4. Result Interpretation

   • High Transmission (>90 %) indicates clear or optically pure materials.

   • Medium Transmission (40–90 %) corresponds to semi‑transparent films or coatings.

   • Low Transmission (<40 %) indicates opaque or heavily pigmented samples.

4. Notes

• Recommended Applications:

  • Optical film transparency testing

  • Coating uniformity verification

  • Glass and polymer transmission profiling

  • UV‑blocking efficiency evaluation