Sample Setup: LED Analysis
When coupled with the optimum sampling accessories, the USB4000 Spectrometer is a highly accurate spectroradiometer for measuring the color, relative power and absolute spectral intensity of LEDs.
A USB4000 Spectrometer optimized for LED measurements is configured with a Grating #2, a 350-1000 nm wavelength range, a 25 m Slit entrance aperture and an L4 Detector Collection Lens to increase light efficiency and reduce stray light. With this configuration, optical resolution is ~1.33 nm (FWHM). An OFLV-350-1000 Order-sorting Filter eliminates second- and third-order effects. This optical bench configuration maximizes system sensitivity, mitigating the light loss inherent with use of an integrating sphere -- the sampling optic of choice for most LED applications. (You also can collect LED signal with a CC-3-UV Cosine Corrector and fiber.)
The LED is mounted in the NIST-traceable LED-PS-NIST LED Power Supply, which provides a white background for the LED and a controlled drive current to characterize LED output. The FOIS-1 Integrating Sphere is placed over the LED-PS-NIST and collects the LED output. The attached optical fiber collects the light energy from the LED and transmits it to the spectrometer. The power and color of the LED is determined by comparing the LED to a radiant standard -- the LS-1-CAL-INT Calibrated Source, which fits into the sample port of the FOIS-1.
LED Power Supply: Secures, Powers & Drives LED
The LED-PS Power Supply provides three useful functions: securing the LED in place, powering the LED, and displaying the LEDs drive current. Use the adjustable drive current feature to increase or decrease an LEDs current up to 50 mA. We offer a standard LED-PS and a NIST-traceable version.
Integrating Sphere: 360?Energy Collection
The LED is powered by the LED-PS and is inserted into the 9.5-mm diameter port of the FOIS-1 Fiber Optic Integrating Sphere, which has a 360?field of view. The P400-2-VIS-NIR Optical Fiber collects the light from the FOIS-1 and funnels it to the USB4000 Spectrometer.
Light Source: Radiometric Reference Source
The LS-1-CAL-INT is a NIST-traceable light source designed specifically to calibrate the spectral response of a spectroradiometric system that uses the FOIS-1 as the sampling device. It provides known absolute intensity values at several wavelengths. The LS-1 is used as a reference for relative power measurements.
Spectral & Color Measurement
SpectraSuite Spectroscopy Operating Software provides absolute spectral intensities for LEDs, znd calculates absolute irradiance, L*a*b*, XYZ, xyz, u'v'w', hue, RGB, chroma, saturation and more.