OL 455 High-Intensity Integrating Sphere Calibration Standard0 pages

Bulletin 108 / Rev. 9-06
Page 1 of 2
OL Series 455
Integrating Sphere Calibration Standard
GENERAL
The OL Series 455 Integrating Sphere Calibration
Standard is designed for accurately calibrating
microphotometers, image intensifiers, telephotometers
and imaging spectroradiometers for photometric,
radiometric, or spectroradiometric response. It serves as
a highly accurate, large area, uniform, diffusely radiating
source with a near normal luminance that can be varied
over 6 decades with essentially constant color
temperature.
The OL Series 455 consists of an optics head and a
separate electronic display console/ power supply (OL
400-C Controller). This enables remote location of either
unit, which facilitates alignment or positioning of the
source with respect to the device to be calibrated. The
source module/ optics head is designed such that it can
be configured with integrating spheres having diameters
of 4, 6, 8, 12 and 18 inches with exit (radiating) ports of
1, 1½, 2, 3 and 6 inches, respectively.
OPTICS HEAD
The optics head has a 150-W tungsten-halogen
reflectorized lamp with a micrometer-controlled variable
aperture between the lamp and the entrance port of the
integrating sphere. This combination provides for
continuous adjustment of the sphere luminance over a
range of more than 106. A precision silicon detector-filter
combination with an accurate photopic response is
mounted in the sphere wall and monitors the sphere
luminance. The in-line sphere port concept with an
intermediate spider baffle provides exceptional high
luminance levels while maintaining high uniformity in the
near normal luminance across the radiating aperture.
A shutter is located between the lamp and the entrance
port of the integrating sphere. The location of the shutter
ensures that any stray light (room light) entering the
radiating port of the sphere is properly accounted for
when auto-zeroing the photometer.
In addition, the source output can easily be set to zero by
use of the shutter without any changes to the sphere
luminance setting.
An optional filter holder, mounted at the exit port,
accommodates alignment targets, filters, de-coupling
diffusers etc. for specific user requirements. Spectral
shaping filters can be utilized to simulate various sources
such as Illuminant A, B, C, D65, etc. In addition to
luminance and color temperature, the OL Series 455 can
be obtained with calibrations for spectral radiance over
all or part of the entire 350 to 2500 nm wavelength
range.
CONTROLLER
The microprocessor-based OL 400-C Controller performs
all system interface and monitoring functions. An
automatic ramp up/ down function eliminates potentially
dangerous current surges to the lamp. Luminance, color
temperature, and lamp current are displayed on a 2 line by
20 character alphanumeric LED display, which may be
turned off for low-light level conditions. An 8 key keypad
and main power switch are located on the front panel for
easy access to all system functions. Luminance is
displayed with 4 ½ digits plus exponent in units specified
by the user. As an option, the display can be factory
programmed to read in virtually any pertinent units the
user desires. DC current supplied to the lamp has a 0.001
ampere resolution with a 0.02% uncertainty. The
controller computes the color temperature of the source
over the range of 2000 – 3000K. Software for remote
operation of the source including on/off and lamp current
setting functions, as well as the photometer read-out units
via full speed USB 2.0 interface, is included. An optional
software development kit is available for custom
programming.