BRDF/BTDF tester

This measuring device is used for measuring the scattering characteristics of various materials. The measurement of sample reflection and transmission radiance under different geometric conditions of incidence and reflection (transmission) is achieved through one-dimensional rotation of the light source and two-dimensional rotation of the detector. The system includes a collimated light source, a light source bracket, an adjustable sample bracket, a detector, a detector rotation mechanism, a detector bracket, and testing software.

BRDF/BTDF testerMain testing parameters

Polychromatic and Monochromatic BRDF

Polychromatic and Monochromatic BTDF

Reflected and transmitted light flux at different angles

Reflected and transmitted radiance at different angles

Scattering light temperature and color coordinates of materials from different angles

BRDF/BTDF tester system architecture

1. Light source

To improve the signal-to-noise ratio of the scattered signal of the sample, a wide spectrum and high brightness tungsten halogen lamp is used as the light source, and the light is collimated through a collimating lens and emitted onto the sample.

By adjusting the focal length of the lens, different sizes of light spots can be achieved.

The light source can also be equipped with a filter to achieve monochromatic light of different colors.

2 Light source bracket

By using a semi-circular light source bracket, the incident angle of the light source can be adjusted from 0 to 180 degrees.

Using high-precision stepper motors and software control to ensure the accuracy of the incident angle.

3. Adjustable sample holder

The sample can be clamped on the sample holder.

The sample holder can be adjusted up and down, and the sample position can be adjusted and aligned by aligning the mark with the light source and detector.

4. Detector

Using a silicon detector with a detection range of 300nm-1000nm.

When measuring scattering characteristics, an optional detection system can be installed, mainly including an imaging optical system, chopper, monochromator, detector, and lock-in amplifier. The imaging optical system images the measuring point of the sample diffuser plate, with the image located at the entrance slit of the monochromator. The polychromatic light enters the monochromator through the incident slit and is collimated before being split by a grating. It is then converged by a converging mirror onto a detector, which converts the optical signal into an electrical signal. The signal is amplified by a lock-in amplifier and extracted based on the chopper frequency to obtain the spectral DN value.

5. Detector bracket and rotating mechanism

The detector bracket and rotating mechanism can move the detector throughout the entire spherical range, enabling measurement of reflected and transmitted signals.

Adopting high-precision stepper motors and software control to ensure the accuracy of reflection and transmission angles.

6. Software section

In order to improve measurement speed and accuracy, a measurement and control software has been specially developed for the device, which supports automatic measurement of scattering characteristics under various geometric conditions at once. Firstly, measure the incident radiance of the light source, and then measure the reflected radiance of the sample diffuser plate under geometric conditions. Repeat this process until all the scattering characteristic measurements under the set geometric conditions are completed, and the software directly outputs the scattering characteristic curve.

Software testing interface