Integrating Spheres - Luminous Flux Measurement for LEDs and Lamps


One of the most important tests in light measurement is the assessment of the total radiant power or luminous flux of light sources using integrating spheres. An integrating sphere’s inside surface is coated with a diffusely reflecting material which guarantees complete integration and homogenization of the emitted radiation. The integrated light is then measured at the detector port.

A complete series of integrating spheres has been developed by Instrument Systems and is available in a wide range of sizes to provide functionality for a broad spectrum of applications. The maximum dimension of the light source to be measured provides the deciding factor in choosing the appropriate integrating sphere. Larger sources require the use of larger integrating spheres in order to keep measurement errors to a minimum.

Instrument Systems integrating spheres all have a side entrance port for determining luminous flux in the 2π configuration (i.e. for determining emission into the forward hemisphere only). With larger integrating spheres, the test object can be mounted in the center, permitting measurements in the 4π configuration (i.e. for determining emission in all directions).

PDFClick here for the Integrating Spheres Brochure.

Model Overview

Model Diameter Entrance port on side Internal lamp post Features Application
ISP 75 75 mm yes no can be coupled to LED Station; version available for use with LED Tester only compatible with standard single LEDs
ISP 100 100 mm yes no Optimized for integration in the LED production environment. Ideal for applications with an LED handler or a wafer prober. Compatible with single LEDs and LED chips
ISP 150L 150 mm yes no for lab and production applications; version available for use with LED handlers and waferprobers; 2π measurements for all single and high power LEDs
ISP 250 250 mm yes no CIE 127 compliant for 2π measurements for all single and high power LEDs as well as small LED modules
ISP 500 500 mm yes yes CIE 127 compliant for 2π measurements compatible with all LEDs, mid-sized modules and small lamps
ISP 1000 1000 mm yes yes lamp post for both standing and hanging arrangements; stable mounting platform for large test sources compatible with all high power LEDs, large modules and lamps
ISP 2000 1900 mm yes yes lamp post for both standing and hanging arrangements; stable mounting platform for large test sources compatible with all kind of lamps, luminaires and SSL products>

Model Specifications

ISP 75

ISP 150L

  • An inner diameter of 75 mm
  • Can be mounted directly on the base or on an LED Station
  • LED test space LED-5xx and -6xx
  • When using in conjunction with an LED sorting machine, the ISP 75 is available with no port flange

ISP 100

  • An inner diameter of 100 mm
  • Single LEDs and LED chip applications
  • Optimum size for constricted space in the wafer prober
  • 33 mm measuring port
  • Optional: Protective silica glass window for the measuring port
ISP 250

ISP 250

  • An inner diameter of 250 mm
  • CIE 127 compliant for measuring luminous flux of LEDs
  • 75 mm minuscule port for coupling from the side
  • version available for use with LED handlers and waferprobers
  • optional auxiliary light source
ISP 500

ISP 500

  • An inner diameter of 500 mm
  • CIE 127 compliant for measuring luminous flux of LEDs
  • 150 mm minuscule port for coupling from the side
  • internal lamp post for mounting test sources in the center
  • auxiliary light source
ISP 1000

ISP 1000

  • Measurement of total radiant power and total luminous flux of high-power LEDs, LED modules, and lamps
  • 300mm minuscule port for coupling from the side
  • Adapter plates for LED test sockets of the type LED-5xx, 6xx and -81x and for TEC test adapter of the type LED-850
  • Lamp post for measuring light sources positioned in an upright or suspended configuration
  • Auxiliary lamp to compensate for self-absorption
ISP 2000

ISP 2000

  • 1.9 m inner diameter
  • lamp post for measuring light sources in an upright or suspended configuration
  • robust and universal sample stage for all kinds of luminaires and SSL products
  • broad variety of standard lamp sockets for use with the internal lamp post
  • 600 mm external measurement port for launching light radiation from outside
  • auxiliary lamp to compensate for self-absorption