Pro Lite Technology

Beam Pattern Testing (2D Spatial Illuminance Measurements)

Beam Pattern Testing

The Westboro BP100 is a compact, portable photometric or colorimetric measurement accessory enabling fast and precise beam pattern measurements of directional light sources and fiber optic illuminators. The method uses a diffusely transmitting screen to provide a flat image that can be measured by a Westboro imaging photometer or colorimeter.

The Westboro Photonics BP100

The BP100 is an accessory kit that is designed to be used with a Westboro imaging photometer or colorimeter for characterising the beam projected beam pattern (2D spatial illuminance distribution) from small or directional light sources, such as spot lamps and fibre optic illuminators. The device under test illuminates the rear of a diffusely transmitting screen. The imaging photometer or colorimeter then views the beam pattern from the other side of the screen.

BP100With Westboro's Photometrica® software, users can perform a menu-driven, geometrical and photometric calibration process. Two-dimensional (2D) measurements can report the intensity of the test lamp in polar (θ, φ) or Cartesian (θH, θV) coordinates. Other computations include illuminance and luminous flux. Chromaticity coordinates and spectral properties can also be measured when using an imaging colorimeter: WP6 Series, WP214, or MCIC.

Without extending the rails or increasing the screen size, the BP100 is well suited to measuring the beam patterns of lamps up to about 25mm in diameter and at wide angles. Somewhat larger lamps may be accommodated by a configuration with enlarged mechanics.

Larger lamps or lamps where the distance to the photometric far-field can be considerable (e.g. automotive head-lamps) are best measured in reflection mode on a wide, diffusely reflecting wall. Photometrica software supports intensity measurements in reflection mode as well. The highly configurable BP100 system includes all beam pattern measurement components except for the imaging photometer or colorimeter and a gauge for measuring distance.

The image below shows the beam pattern of a torch: the chart on the left is an iso-candela diagram, while that on the right is a 3D representation of the intensity distribution.

Advantages of Projected Beam Pattern Testing

Goniometers are the traditional way to measure lamp properties as a function of angle of emission. These systems are usually relatively expensive and dedicated for one specific measurement.The BP100 system in contrast has the following advantages:

  • It can be assembled and disassembled in minutes
  • You can obtain high resolution measurements
  • You can acquire 2D high dynamic range images in seconds
  • You can share the imager for other measurements in the laboratory

BP100Key Specifications

Together with your choice of Westboro imaging photometer or colorimeter, the BP100 can measure luminous intensity values from 0.1 to 300,000 candelas amd illuminance from 0.2 to 750,000 lux. The lamp-to-screen distance can be set between 60 to 750mm and the measurement resolution is <0.3°. The lamp beam angle can range between 28 to 144° full angle. These specifications are based upon using the Westboro P230U, 2.3MP CMOS imager and >10:1 signal to noise ratio.

The image right shows the angular luminous intensity profile of a "bat wing" LED compared with traditional goniophotometric data.

Choice of Imagers

The BP100 works with a range of imagers from Westboro Photonics. Choose the WP6 series imaging colorimeter for intensity and color distribution data; or a SMART series USB3 CMOS photometer if colour is not required.

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