Medium Area Uniform Light Sources

Labsphere USS-1200 Medium Area Uniform Light Source

Exceptional luminance uniformity over 4 or 8 inch exit ports

The Labsphere USS-1200 and USS-2000 uniform light sources are based upon 12 and 20 inch integrating spheres respectively and provide exceptional luminance uniformity over their 4 and 8 inch exit ports. Medium area uniform sources are commonly used to test and calibrate imaging photometers and CCD cameras, remote sensing instruments and focal plane array detectors.

The 12 inch source is offered in two versions. The USS-1200S employs 4 internally mounted 35 Watt tungsten halogen lamps that can be turned on or off individually to provide step-wise luminance adjustment from 10,000 to 40,000 cd/m². The USS-1200C also employs 4 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 3 internal lamps) from zero to 40,000 cd/m². At peak luminance, uniformity across the full area of the exit port is 98%.

The 20 inch source is also available as the USS-2000S with 4 internal 35 Watt halogen lamps (luminance can be varied in steps from 4,600 to 18,000 cd/m²) and as the USS-2000C with 3 internal and 1 external lamp and variable attenuator (giving zero to 18,000 cd/m²). Luminance uniformity is also specified at 98% or better across the full exit port at peak luminance.

All lamps used in the medium 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 for bench use. 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 & System Configurations

Main Specifications	USS-1200S	USS-1200C	USS-2000S	USS-2000C
Sphere Type	US-120-SF	US-1200-SF	US-200-SF	US-200-SF
Integrating Sphere Dia. (inches)	12	12	20	20
Exit Port Dia. (inches)	4	4	8	8
Luminance (cd/m²)	10,000 - 40,000	0 - 40,000	4,600 - 18,000	0 - 18,000
Uniformity (%)	98	98	98	98
Colour Temperature (Kelvin)	3,000	3,000	3,000	3,000
Peak Radiance (mW/cm².sr.µm @ 900nm)	98.5	98.5	55	55
System Configuration
Internal Lamps
IHLS-100-35 (35W)	x 4	x 3	x 4	x 3
External Lamps
EHLS-100-100R (100W)	-	x 1	-	x 1
Power Supplies
LPS-100-0833 (100W)	-	x 1	-	x 1
LPS-100-0307 (35W)	x 4	x 3	x 4	x 3
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