LED Testing & Analysis
LED optical testing for electronic assemblies and production lines
Iber Tekno develops LED testing solutions using varies analysers, fibre-optic light guides and application-specific measurement accessories. We help manufacturers verify LED colour, brightness and wavelength, identify inconsistent light output, and integrate repeatable optical measurements into production testing.
Our solutions cover PCB indicators, RGB lighting, illuminated switches, infrared LEDs, displays and automotive lighting. We select the appropriate equipment, optical arrangement and test method for your product requirements.
More than an LED on/off check An LED can illuminate and still fail your product requirements. It may produce the wrong colour, insufficient brightness or a different shade from neighbouring LEDs. Optical testing measures these characteristics and compares the results with defined acceptance limits. This helps detect assembly errors, incorrect components and inconsistent illumination before products leave the production line.
Our LED testing capabilities
LED colour verification
Verify that each LED produces the expected colour and falls within your specified acceptance limits.
Depending on the selected analyser and interface, colour measurements can include:
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Red, green and blue values-RGB
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Hue and saturation
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CIE xy chromaticity coordinates
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CIE u′v′ chromaticity coordinates
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Dominant wavelength
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Correlated colour temperature-CCT
These measurements support colour identification and consistency checks for individual LEDs and assembled products.
LED brightness and relative intensity testing
Check whether each LED produces sufficient light output and compare its intensity with an agreed reference or acceptance range.Relative intensity testing can help identify dim LEDs and differences between LEDs that should perform consistently. Reliable comparison requires controlled operating conditions and repeatable positioning of the optical fibres or heads.
Colour consistency and chromaticity
Measure colour coordinates to evaluate differences that may be difficult to judge consistently by eye.Chromaticity testing is useful for matching illuminated buttons, indicators, lighting modules and backlit panels. It allows colour tolerances to be defined numerically and checked during production
White LED colour temperature — CCT
Evaluate the warm or cool appearance of white LEDs using correlated colour temperature, expressed in kelvin.
CCT testing supports white-light selection and consistency checks. Where precise white-colour matching is required, CCT can be assessed together with chromaticity coordinates.
Dominant wavelength measurement
Evaluate the perceived colour of coloured LEDs using dominant wavelength, expressed in nanometres.This measurement supports verification of coloured indicators and lighting assemblies against specified colour ranges
RGB LED testing and colour mixing
Test RGB LEDs and verify the colours produced by combining their red, green and blue channels.Application-specific testing can include individual colour-channel checks, mixed-colour verification, intensity comparison and measurements supporting RGB module calibration.
Typical applications include ambient lighting, illuminated switches, control panels and colour-changing LED assemblies.
Low-light and backlit component testing
Evaluate illuminated components where the available light level is low or light passes through a diffuser, painted surface or etched panel.
Dedicated low-light solutions support colour and intensity checks for:
- Illuminated switches and buttons
- Backlit symbols and legends
- Automotive dashboard controls
- Instrument and control panels
- Low-intensity indicators
Infrared LED testing
Measure infrared LED wavelength and intensity using the dedicated products infrared analyser, suitable fibres and optical heads.
The published operating range of the IR analyser is 700–950 nm.
This supports applications such as infrared illumination and sensing assemblies.
The appropriate measurement configuration is selected according to the emitter wavelength, output level and available optical access.
LED spectral measurement
Use the LED spectrometer for visible-light analysis within its published 380–780 nm operating range.
Spectrometer-based measurements support colour analysis, RGB colour mixing and reference measurements for production test setups. The instrument includes automatic exposure control and range selection.
Luminous flux measurement — lumens
Measure total visible light output using a suitable spectrometer and integrating-sphere arrangement.
Luminous flux measurements are expressed in lumens and are useful when an absolute light-output value is required.
The sphere, collection geometry and calibration must be appropriate for the LED being tested.
Luminous intensity measurement — cd or mcd
Measure visible light output in a defined direction using the appropriate luminous-intensity measurement head and spectrometer.
Results can be expressed in candela or millicandela. This measurement is useful when the directional output of an LED is relevant to the product specification.
Luminance measurement — cd/m²
Measure the brightness of an emitting surface in a defined viewing direction.Luminance testing supports the evaluation of displays, illuminated panels and other emitting surfaces. Measurements are expressed in candela per square metre.
Display testing
Configure optical testing for displays to evaluate:
- Luminance- Chromaticity and colour consistency
- Contrast ratio
Display measurements are performed under defined operating and measurement conditions to support meaningful comparison with product requirements.
Automotive LED and matrix headlight testing
Develop production test arrangements for high-brightness automotive LEDs and matrix headlight assemblies.
Suitable analysers and optical heads allow individual LEDs to be evaluated where spacing and access require specialised collection arrangements.
Applications include headlight LED modules, daytime running lights, brake lights, indicators and interior lighting.
Flashing, blinking and PWM-driven LED testing
Measure LEDs operating in flashing, blinking or pulse-width-modulated modes using suitable capture settings.
The test method is selected according to the LED operating sequence, pulse behaviour and required optical measurement. Capture timing and repeatability are validated for the application.
Seven-segment and bargraph display testing
Verify illuminated segments individually by positioning optical collection points at the relevant locations.
This supports segment illumination, colour and intensity checks for numeric displays, status bars and indicator assemblies.
Automated LED testing and system integration
Iber Tekno integrates LED optical measurements into functional test systems, in-circuit test workflows and application-specific test fixtures.
The integration is configured around your product, LED count and production requirements.
It can include:
- Multichannel LED measurement- Coordinated LED activation and measurement capture
- Application-specific optical fibre and head positioning
- Comparison against defined acceptance limits
- Automated pass/fail evaluation
- Reference-based test setup
- Communication with the production test software
The equipment offers USB, RS232 and model-specific ICT interfaces. Available software resources include DLLs, LabVIEW support and programming examples. Interface selection depends on the chosen equipment and test platform.
How fibre-optic LED testing works
1. Operate the LEDs
The board or test system powers the LEDs in the required operating state.
2. Collect the emitted light
Optical fibres or suitable optical heads are positioned near the LEDs. They collect emitted light and guide it to the analyser.
3. Measure the optical output
The analyser evaluates the available colour, intensity and wavelength parameters.
4. Compare with acceptance limits
The test software compares measurements with your product specification or an agreed reference-based test method.
5. Identify passing and failing results
The system determines whether each measured LED meets the defined criteria.
LED types and applications
We configure testing solutions for a wide range of LED packages and assemblies, including:
- Surface-mount and through-hole LEDs
- Single-colour and white LEDs
- Bi-colour and tri-colour LEDs
- RGB LEDs and modules
- COB and multichip LED assemblies
- Infrared LEDs within the supported measurement range
- Seven-segment and bargraph displays
- PCB status indicators
- Illuminated switches, symbols and control panels
- Display backlighting
- Automotive interior and exterior lighting assemblies
Measurement feasibility depends on optical access, wavelength, light output, component spacing and operating conditions.
A test solution matched to your product
We begin with your measurement requirements and select the equipment and integration approach accordingly.
The project definition considers:
- LED part numbers, packages and wavelengths
- Number of LEDs and their positions
- Required colours and operating modes
- Required optical measurements
- Acceptance limits and reference samples
- Target production cycle time
- Fixture access and positioning
- Communication with your existing test system
- Calibration requirements for absolute measurements
This approach creates a test method suited to your assembly and production process.
Frequently asked questions
Can you test several LEDs in one system?
Yes. The equipment offers multichannel analysers and expansion arrangements. The number of channels and the test sequence are selected according to your product and cycle-time requirements.
Do the optical fibres electrically contact the LEDs?
The fibres collect emitted light. Electrical power and control are provided separately by the board or test system. The optical arrangement is selected for suitable access and repeatable light collection.
Can you test whether an LED is the correct colour?
Yes. Available measurements such as RGB, hue, chromaticity and dominant wavelength can be compared with defined colour limits.
Can you check whether neighbouring LEDs match?
Yes. Colour and intensity measurements can be compared under controlled conditions to evaluate consistency between LEDs or illuminated areas.
Can you measure lumens with every LED analyser?
Luminous flux measurements require an appropriate spectrometer, integrating sphere and calibration arrangement. Standard analyser relative-intensity readings are not automatically measurements in lumens.
Can you test infrared LEDs?
Yes. The dedicated FEASA infrared analyser measures wavelength and intensity within its published 700–950 nm operating range.
Can LED testing be integrated into an existing production test system?
Yes. Integration can be configured using the interfaces available on the selected FEASA equipment and the capabilities of your existing test platform.
How are pass/fail limits established?
Limits are based on your product specification or an agreed reference-based method. The measurement setup is then validated using representative products.
Does one the model perform every measurement?
Different measurements require different analysers, optical heads and accessories. We select the configuration needed for the application.
Discuss your LED testing requirement
Tell us about your product, the LEDs you use and the measurements you need. Our team can help define an LED test solution for your electronic assembly or production line.For an initial assessment, share the LED part numbers, board layout, LED count, acceptance criteria and target cycle time.