The Advantages of Spectral vs. Filter Color Measurement Systems

Although filter based instruments are desired for certain properties such as cost, speed and portability, they are not always the best choice for analytical measurements. Filter based instruments only acquire three data points across the entire spectrum of light to yield colorimetric values. This is accomplished by the use of filters corresponding to the normal human eye response. These filters can only be manufactured to a certain degree of accuracy. Due to these facts, filter based meters are susceptible to errors because of the deviation of the filter response from the ideal human eye response and the lack of resolution needed to accurately describe narrow bandwidth light sources.

Spectral Irradiance Meters avoid these problems at a comparable cost, higher speed and small footprint because it acquires hundreds of data points across the visible spectrum. In addition, the 2048 pixel linear CCD array provides the precision required to accurately measure narrow bandwidth light sources or LEDs. Having multiple sensors also enables the unit to report spectral data and display spectral graphs, making it the ideal instrument for evaluating LEDs, which are today’s dominant light source.

SpectraRad™ Xpress   Power Input USB at < 350 mA Detector Type Response enhanced 2048 element linear silicon CCD array Detector Pixel Format 2048 x 1 elements @ 14μm x 200μm per element Spectrograph F# 3.0 Spectrograph Optical Layout Crossed Czerny-Turner Dynamic Range 275 typical Digitizer Resolution 16-bit or 65,535:1 Readout Speed 500 kHz Data Transfer Speed Up to 180 spectra per second via USB 2.0 Effective Integration Time 1 to >=20,000 ms External Trigger Aux Port Operating Temperature 15°C - 35°C Relative Humidity 0 - 85% RH non condensing Weight ~0.23 kg (0.5 lbs) Dimensions See Drawings Computer Interface USB 2.0/1.1 Operating Systems Windows XP, Vista (32-bit), & 7 (32-bit)

SpectraRad™ Optical Spectral Range 380nm - 750nm,  350nm - 1050nm Spectral Resolution ~1.5nm,  ~2.0nm Irradiance Range 25 nW/cm2/nm - 4 mW/cm2/nm Electrical Detector Type Response Enhanced 2048 element linear silicon CCD array TE Cooling 14°C External Trigger Aux Port Computer Interface USB 2.0 / 1.1 Data Transfer Speed Up to 180 spectra per second via USB 2.0 DC Power Input 5V DC < 1.5 Amps Software Effective Integration Time 5 - 120,000ms Operating Systems Windows: XP, Vista (32-bit), 7 (32-bit) Environmental Operating Temperature 15°C - 35°C Operational Relative Humidity 85% Noncondensing