Integrating LED tests in functional and in-circuit test fixtures

LED testers are used to measure hue (color) and intensity of a LED. They are available in a variety of models with some limited to a specific task such as detecting a particular color or checking if a LED is on or off. The LED light characteristics are analyzed by a sensor and the results are returned as a voltage that can then be software-interpreted (or not) to get the light intensity, color, correlated colour temperature and other useful information.

LED testers can be used in both functional and in-circuit test fixtures. In the case of ICT fixtures, LED to be tested are usually soldered to a PCB. Fiber-optic probes are placed near the LEDs to test and connected to LED sensors. The sensors are wired to the fixture's base so that the measurement results can be read through the tester.

LED sensors in an in-circuit test fixture

For functional fixtures, LED to test can also be on the final product enclosure for "as used" functional testing. Some "user-friendly" LED testing solutions are available for customers who don't want to manually interpret the voltage results or develop software for it. The company Feasa, for example, offers a solution with an USB interface and a software to read the results on a personal computer.

Rematek offer several brands of LED analyzer such as Optomistic, Feasa and FINN Test Electronics (Test Coach).

Feasa

The Feasa Analyser is an innovative solution for testing multiple LEDs simultaneously for color and brightness. There are two models: Feasa-I (ICT) and Feasa-F (Functional). These can be ordered in 3, 5, 10 and 20 channel configurations.

Feasa LED Analyser promo video

When choosing which model is most suitable for your application there are a number of issues to consider. In this regard the choice of interface is very important.

Feasa is also offering the Feasa LEGEND; a ready-to-use solution with USB and RS232 interface. The Feasa LEGEND provides an easy to use Graphical User Interface (GUI) to automatically learn and store pass/fail criteria for up to 32 different versions of boards reducing the complexity and development time of test programs.

The Feasa LEGEND systems consists of two component parts, a hub and a LED analyzer. The hub can be mounted in the test station or in the test fixture and can control up to eight LED analyzers. Each LED analyzer can test up to 20 LEDs and a fully populated hub can test up to 160 LEDs. Hubs may be added together to test a larger number of LEDs.

This is a great product to use with multiple LED applications.

The Feasa LEGEND

FINN Test Electronics

FINN Test Electronics family of products have the particularity of not making use of any optical cables. Because the sensors are so small, they can be easily mounted in the fixture near the LEDs to test.

Some LED sensors of the FINN Test Electronics family of products

Optomistic

Optomistic Universal LightProbes offer a unique 2-part solution that addresses almost every LED test requirement you may have.

You start by choosing a pre-programmed sensor for the type of test and output you require, then, combine it with an interchangeable fiber-optic probe to further customize the test for mechanical requirements and constraints. Output can be analog, digital (to test a single color with a one-bit PASS/FAIL test output) or serial digital/USB interface (for a direct connection to a PC USB port).

Optomistic Universal LightProbes

You start by choosing a sensor for the type of test and output you require:

Optomistic sensor selection chart

After you have chosen the sensor that fits your LED test requirements, you will want to match it with a fiber-optic probe that will provide the best solution (small aperture, wide aperture, wide aperture with contacting tip) to your specific LED test application.

Choose the right fiber-optic probe for your LED test application

Need more information?

Do not hesitate to contact a Rematek representative to discuss which LED testing product may be the best suited for your project.