This instrument is designed for measuring diffuse transmittance, equipped
with an integrating sphere for the source of diffuse illumination.
The double-beam design provides precise and stable measurements, especially
for transmittance measurement of specimens which are transparent or
translucent. The geometry is also suitable for non-flat samples, such
as concave or convex glass, and lenses. The horizontal specimen table
allows fast, easy placement of samples, and makes much more efficient
use of your operator's time. The DOT-3C can measure very thick samples
(max 30mm), making it ideal for the measurement of the transmitted
color for the lenses of spectacles.
The DOT-3C is well-suited to make measurements of a wide variety
of solid and liquid applications including:
- Determining the color of lenses
- Transmittance of glass and plastics
- Transmittance of filters
- Transmittance of liquids, including beer, wine, whiskey, juices, and edible oils.
The light from the halogen lamp passes through an infrared filter before entering the
integrating sphere. This is to reduce any effect due to warming of the sample. After being
integrated in the sphere, the diffuse light illuminates the sample, and the transmitted light
(sample beam) is directed to the chopper mirror.
A second sphere port allows the reference beam to exit the sphere
without passing through the sample. This beam is also directed to the chopper
The chopper mirror alternately allows either the sample beam or the reference
beam to enter the polychromator. Each beam in turn is dispersed by the concave
grating and imaged onto the detector array.
The shutter at the polychromator entrance is used for measuring the dark current
of the detector array.
Last, a processing step uses the signals for sample beam, reference beam, and dark current to calculate the
spectral transmittance of the sample.
|Measuring Method||Double-beam spectrophotometer|
|Measuring Geometry||Diffuse illumination, normal viewing (d:0°)|
|Viewing Area||4mm x 8mm|
|Illumination Area||40mm diameter|
|Sample Thickness||Maximum 30mm|
|Spectral Range||390nm - 730nm|
|Spectral Bandpass||Approximately 10nm|
||Concave diffraction grating
|Light Source||Halogen lamp, 12V, 50W|
|Detector||35 element silicon photodiode array|
|A/D converter||16 bits|
|Data transfer time||about 4 seconds - variable (1.5 seconds when delivered)|
|Reproducibility||0.03% max standard deviation, 30 measurements of air when data transfer time set to 3 sec|
|Power requirements||100, 50/60Hz|
|Dimensions||324mm x 500mm x 342mm (W x D x H)|
|Power cord||Instrument cover|
|RS-232C cable||Accessory Case|
|Spare Lamp||Instruction manual|