Large Area Uniform Light Sources

A 65 inch Labsphere Uniform Light Source Undergoing a Lumnance Mapping Calibration

Exceptional luminance uniformity over 14 or 22 inch exit ports

Further Information	Technical Drawings
» USS-4000 & USS-6500 Datasheet	» USS-4000 & USS-6500 Drawing

The Labsphere USS-4000 and USS-6500 uniform light sources are based upon 40 and 65 inch integrating spheres respectively and provide exceptional luminance uniformity over their 14 and 22 inch exit ports. Large area uniform sources are used to test and calibrate satellite spectroradiometers as well as electronic imaging equipment and focal plane array detectors.

The 40 inch source is offered in two versions. The USS-4000S employs 10 internally mounted tungsten halogen lamps that can be turned on or off individually to provide step-wise luminance adjustment from 1,660 to 40,000 cd/m². The USS-4000C also employs 10 lamps but one of these is a 100 Watt external lamp which is coupled into the sphere via a motorised variable attenuator. This provides for continous luminance adjustment (in conjunction with the 9 internal lamps) from zero to 40,000 cd/m². At peak luminance, uniformity across the full area of the exit port is 98%.

The 65 inch source is also available as the USS-6500S with 20 internal halogen lamps (luminance can be varied in steps from 640 to 34,400 cd/m²) and as the USS-6500C with 19 internal and 1 external lamp and variable attenuator (giving zero to 34,400 cd/m²). Luminance uniformity is also specified at 98% or better across the full exit port at peak luminance.

All lamps used in the large area uniform light sources burn at a correlated colour temperature of 3,000 Kelvin. Each system is supplied with current regulated lamp power supplies and a calibrated photometer that records the luminance from the sphere and displays this reading in cd/m². All spheres are supplied with a sturdy extruded aluminium frame and carriage with lockable castors. The lamp power supplies and monitor photometer are mounted in a separate rack. Optional calibrations include measurements of the source illuminance, spectral radiance (300-2400nm) and integrated radiance. Luminance uniformity mappings of the sphere are also available, both spatial and angular.

Specifications and System Configurations

Main Specifications	USS-4000S	USS-4000C	USS-6500S	USS-6500C
Sphere Type	US-400-SF	US-400-SF	US-650-SF	US-650-SF
Integrating Sphere Dia. (inches)	40	40	65	65
Exit Port Dia. (inches)	14	14	22	22
Luminance (cd/m²)	1,660 - 40,000	0 - 40,000	650 - 34,400	0 - 34,400
Uniformity (%)	98	98	98	98
Colour Temperature (Kelvin)	3,000	3,000	3,000	3,000
Peak Radiance (mW/cm².sr.µm @ 900nm)	117	117	99	99
System Configuration
Internal Lamps
IHLS-DM-150 (150W)	x 7	x 7	x 17	x 17
IHLS-100-75 (75W)	x 2	x 1	x 2	x 1
IHLS-100-35 (35W)	x 1	x 1	x 1	x 1
External Lamps
EHLS-100-100R (100W)	-	x 1	-	x 1
Power Supplies
LPS-150-0635 (150W)	x 7	x 7	x 17	x 17
LPS-100-0833 (100W)	-	x 1	-	x 1
LPS-100-0625 (75W)	x 2	x 1	x 2	x 1
LPS-100-0307 (35W)	x 1	x 1	x 1	x 1
Variable Attenuator	-	1 x VA-100-SC	-	1 x VA-100-SC
Variable Attenuator Controller	-	1 x MC-1000	-	1 x MC-1000
Monitor Detector	SDA-050-P-RTA-CE (photopic response)
Monitor Photometer / System Controller	SC-6000
Standard Calibrations	Luminance (cd/m²)
Optional Calibrations	Spectral radiance (mW/cm².sr.µm, 300-2400nm)
	Illuminance (lux)
	Integrated Radiance (W/sr)
	Luminance mapping