Modular Integrating Spheres from Gigahertz Optik GmbH

Integrating Spheres (UM)* are an important component of many optical systems. They are used as detectors for measuring all kinds of divergent light sources. When used as a light source, they provide uniform light fields with diffuse radiation. In the photometric analysis of materials they enable the measurement of reflection, transmission, absorption, photoluminescence, etc.

In addition to an extensive range of standard products, Gigahertz Optik GmbH offers individually configured integrating spheres. These bespoke integrating spheres permit many unique features including the tailored positioning, design and number of ports.

This paper describes UM-modular system concept, including the various sphere assemblies and accessories that enable complete sphere systems to be built.  Configuring your own modular integrating sphere is described in 10 easy steps. Some example configurations illustrate the range of possibilities with the UM-modular system.

*  Also known as Ulbricht spheres after the engineer Richard Ulbricht (1849-1923) credited with its invention. The M stands for Modular Concept.

Integrating Sphere Detectors not only measure the luminous flux and radiant power of lamps, LEDs and luminaires, but also of lasers, laser diodes, optical fibers and endoscopes.

Integrating sphere light sources, often referred to as Uniform Light Sources, offer diffuse radiation with high uniformity of luminance or radiance. Typical applications include white pixel balancing of digital camera systems, characterization of CMOS and CCD sensors, hyperspectral systems, measuring scattered light (veiling glare), calibration of measuring instruments for luminance and spectral radiance, target illumination.

Integrating Spheres for measuring photometric material properties such as reflection, transmission, absorption, photoluminescence.

a) ISD integrating sphere detectors

b) ISM integrating spheres for material assessment (measurement of reflection, transmission, absorption, photoluminescence, etc.)

c) ISS Integrating Sphere Light Sources (luminance and radiance standards, uniform light sources)

First, take a look at our standard range of preconfigured integrating spheres including: integrating sphere detectors (ISD); integrating sphere light sources (ISS); and integrating spheres for material characterization. In addition to these three main application types we offer the UP series. The housings of these integrating spheres are made from precision CNC machined aluminum blocks. This results in the highest precision of spherical shape and geometry and position of the port openings. Selecting a standard product will save you time and money. Our sales team will be happy to assist in the search and selection.

If you have not found a suitable standard integrating sphere type or system for your application, this is the point to start planning the sphere configuration. You’ll need to determine which sphere accessories and metrology accessories from Gigahertz-Optik’s range will be required. This is a good time to consult our sales team to assist you configure your custom integrating sphere.

As a guideline, the following should be considered:

1. Number of port openings - the total area of all sphere openings should not be more than 5% of the internal sphere surface area

2. Diameter of the largest port opening

3. Type, maximum extent and power of the light source(s) to be used internally or externally

4. Wavelength range of the intended application

5. Maximum permissible attenuation of the integrating sphere from the point of the subsequent application and calibration.

A hand sketch of the required sphere configuration is an effective planning tool. A three-panel sketch of the base sphere is recommended showing front, side and top views. This should show any flanges, auxiliary frame or base components in the desired orientation. It is important to ensure that any sphere assemblies and accessories are shown in proportion to the size of the sphere. The presentation of all the required components serves as a reliable template from which a Bill of Materials, BOM, can be produced for manufacturing purposes. Familiarize yourself with the design criteria for integrating spheres - refer to the information portal of our website: Basics of light measurement.

Complete measurement systems can be assembled using the customized sphere in conjunction with additional products from Gigahertz-Optik’s extensive metrology range as well as third party components. In this case, please discus your proposed application so that a technical specification can be drawn up.

Gigahertz-Optik GmbH offers the versatile “S-Series” software for use with the external modules of integrating sphere systems. In addition to many standard routines, “S-Series” software provides the option to add additional functions and to integrate evaluation modules. The S-SDK Software Development Kits enable full remote control from the user's software of sphere accessories, data acquisition systems, variable apertures, power supplies, etc.

The optical radiation calibration laboratory of Gigahertz-Optik GmbH offers traceable calibrations for integrating sphere systems. Possible calibrations include:

1. Calibration of the absolute spectral radiant power sensitivity for ISD integrating sphere detectors. Spectral range 200 nm to 1800 nm.
2. Calibration of luminance in cd / m² of ISS Integrating Sphere Light Sources.
3. Calibration of spectral radiance in W / m²nm or W / m²μm. Spectral range 250 nm to 2500 nm.
4. Calibration of the luminance distribution (uniformity) of ISS Integrating Sphere Light Sources.
5. Calibration of diffuse reflectance standards for ISM integrating spheres for material analysis.

A cost estimate including all the required components and services is issued based on the created sketches and discussed system configuration. Any change requests can be discussed based on the cost estimate.

Once the cost estimate and the sphere configuration are finalized, Gigahertz-Optik GmbH will issue a binding offer. A new part number is created for the entire custom sphere configuration in order to simplify the ordering process and to reduce costs where possible.

Base Spheres

base spheres with flange. Barium sulfate coating.

base spheres with stand or auxiliary frame.Barium sulfate coating.

base spheres with flange.Synthetic ODM98 coating.

base spheres with stand or auxiliary frame. Synthetic ODM98 coating.

Sphere Assemblies 

Port frames with circular V-groove for attaching accessories

for shading two or more ports, samples and sphere center

Sphere Accessories

UMPP

plugs

for use with port frames for closing ports

UMPR

reducers for use with port frames

UMPA

port adapters

for use with auxiliary lamps, Microbenches, fiber-optic connection

UMSH

sample holder

mount and electrical connection of test samples or lamp adapters

UMLA

internal lamp assembly

for reflector halogen lamps, optional filter holder, variable aperture

Measurement Accessories

PD-11

Photodiode detectors

Photometric detectors

Si, InGaAs, V(λ)

For 19” Rack mounting

Benchtop meter for two detectors. RS232 & IEEE488

BTS2048-VL

BTS2048-VL-F

LED measurement adapter

Software

S-SDK

Software