LED and LED Luminaire Testing
 First in Full Range PDA Spectrometer, Spectroradiometer and Spectrophotometer Systems
1 Canal Street  ◊  Unit B1
Lawrence, MA 01840  USA
Tel: 978 687-1833  ◊  Fax: 978 945-0372
Email:
info@spectralevolution.com


Copyright © 2012 Spectral Evolution, Inc
The PSR+ 3500 field portable spectroradiometer can be used to measure and compare the spectral
radiance of an LED (red) versus a halogen(blue) light source. This capability becomes especially
important in those applications where a design engineer is considering replacing a traditional light source
with an LED and needs to verify that the LED luminaire will meet or beat the critical characteristics of the
halogen lamp.
LEDs are fourth generation light-sources that offer increasingly
reliable operation, and overall lower cost when compared with
traditional lighting technologies such as incandescent,
fluorescent, high-intensity discharge (HID), high-pressure
sodium (HPS), and other lighting technologies.  LEDs have long
been used as indicator lights in a wide range of consumer and
machinery display/control products. In automotive they are
moving from dashboard and interior lights to headlights, tail
replacing conventional lighting both internally and externally.
Other popular external applications include emergency lighting,
roadway/street lighting, and runway lighting at airports.

As with any technology, in addition to advantages, there are
drawbacks. Consistent manufacturing of LEDs with the same or
similar optical properties is almost impossible – even for LEDs in
the same batch. Brightness and color can both vary from
component to component. Output is also affected by
encapsulation, the efficiency of different wafer lots, and other
process variables.

Testing of LEDs for light intensity/brightness and color is
important to successful use in all applications.

A SPECTRAL EVOLUTION spectroradiometer  measures the
wavelengths of individual colors of light. In LED metrology it can
measure output in lumens, watts, moles per second, footcandles,
and more. A portable UV/VIS/NIR spectroradiometer  provides a
useful tool for quickly testing and characterizing LEDs and LED
luminaires. It can test an LED for optical output in watts as a
function of varying LED current, temperature, and other optical
characteristics to completely characterize the LED or LED
system. Important spectroradiometer capabilities for LED test
applications could include:
  • Fast, full spectrum UV/VIS/NIR measurements with a
    spectral range from 350 – 2500nm with a single scan
  • Ultra-fast scanning with autoshutter, autoexposure, and
    auto-dark correction before each new scan – without
    requiring repeat optimization steps
  • Fixed array detectors for reliable operation
  • Lightweight and portable for lab or field use
  • Standalone operation or use with a laptop or personal
    digital assistant (PDA)
  • Bluetooth for easy communications
  • Superior signal to noise ratio with faster scan times and
    better reflectance measurement
  • NIST-traceable calibration for taking a wide range of
    irradiance and color measurements to fit all the application
    specifications

In addition, all SPECTRAL EVOLUTION systems have the following
colorimetry capabilities built-in:
  • CIE 1931 chromaticity diagram with RGB gamut
  • Scan results displayed graphically with a cross hair overlay
  • Text display of x, y, XYZ, and RGB coordinates and
    correlated color temperature

The ability to quickly test for brightness and chromaticity in the
lab or in the field allows for rapid screening of LEDs before use
and offers a method for gauging color shift over projected
lifecycle, where color and hues are critical. Since LEDs tend to
shift color over time, measuring color stability can be a key in
many applications. It is also useful to compare the brightness
and color of LEDs versus incandescent, fluorescent or halogen
lamps early in the design process, before the LEDs are used as
substitutes for these conventional lighting technologies.
DARWin SP Data Acquisition software provides a built-in colorimetry capability. It can be used
to calculate chromaticity coordinates and correlated color temperature of a spectral dataset.The
following colorimetry capabilities are built-in:
  • CIE 1931 chromaticity diagram with RGB gamut
  • Scan results displayed graphically with a cross hair overlay
  • Text display of x, y, XYZ, and RGB coordinates and correlated color temperature
The ability to quickly test for brightness and chromaticity in the lab or in the field allows for rapid
screening of LEDs before use and offers a method for gauging color shift over projected
lifecycle, where color and hues are critical. Since LEDs tend to shift color over time, measuring
color stability can be a key in many applications. It is also useful to compare the brightness and
color of LEDs versus incandescent, fluorescent or halogen lamps early in the design process,
before the LEDs are used as substitutes for these conventional lighting technologies.
SPECTRAL EVOLUTION CORPORATE LOGO - FIRST IN UV-VIS-NIR SPECTROMETER, SPECTRORADIOMETER AND SPECTROPHOTOMETER PRODUCTS
 First in Full Range PDA Spectrometer, Spectroradiometer and Spectrophotometer Systems