In short
- LED functionality is how LEDs perform on the assembled PCB: light under each power option, the right color, the right position and order.
- Why test: to prove the batch is free of LED faults and every LED matches the configuration, before boards reach the customer.
- How: an imager with optics and an API that opens the camera, learns the configuration from a JSON file and tests boards, with results in a CSV file.
- No fibers: the IZAK tester images the board in free space and fits into existing test applications.
What is LED functionality?
LED functionality describes how LEDs perform once they are assembled on a PCB. It is checked by observing how the LEDs behave under different power settings and which color they emit.
The check confirms that the LEDs follow the circuit’s configuration. Problems appear when an LED:
- shows the wrong color;
- gives no light under one or more power options;
- sits in the wrong position or in the wrong order relative to the configuration.
For the physics behind LED color and forward voltage, see Understanding LEDs: how they work.
Why is it important to check LED functionality?
An LED color tester evaluates whether the LEDs work, their order and placement, and whether the correct colors are used.
Testing confirms that the system works as required and has no errors left from manufacturing. It ensures that a batch is free of LED faults and that every LED matches the configuration.
Testing helps PCB manufacturers confirm quality and catch defects early. LED tester tools can be added to existing test applications, so the check runs as one more step of the production test.
How many boards will have an LED fault, and how long does the test take?
Enter the LEDs per board, the expected defect rate per LED (wrong part, polarity, placement or a dead LED, in ppm), the batch size and your test timing. The tool estimates how many boards carry at least one faulty LED and the test throughput.
Model: with defect rate p per LED and N LEDs, P(board faulty) = 1 − (1 − p)N; faulty boards = batch × P; LED checks = batch × N × states; test time per board = states × time per state + handling; boards per hour = 3600 / test time. Defects are assumed independent. Your own process data gives the best defect rate.
How can you test LED functionality?
Testing needs a checker tool that identifies the position, operation and color of each LED on PCBs and indication panels. IZAK’s LED color and position tester works without optical fiber connections. It includes an imager with optics and an API with simple commands:
Captures an image from the camera, or loads an existing image from a file path.
Loads a JSON configuration file, so the system learns the LED layout before it tests a batch.
Evaluates all LEDs against the learned configuration and logs the results to a .csv file.
The system is simple to use. It tests a whole batch of boards with a similar configuration, reports whether the configuration and colors are correct, and flags missing, mismatched or defective LEDs.
To see how the tester recognizes color and position, read LED tester of color and position: how does it work?, and for line integration, how to embed an LED checker into your production line.
Watch: the LED tester checking colour and position
Customer story: LED color and position tester in a production test system
A global manufacturer of semiconductor-equipment subsystems bought an LED color and position tester from IZAK Scientific after several successful earlier projects with our team. They needed to test PCBs that carry several LED configurations each.
IZAK supplied the recognition API as a DLL with a ready C integration example, which the customer integrated into its own tester software, and a tester box with an imager, optics and relays.
What the customer said
“A simple, easy-to-learn machine-learning tool that learns a new PCB in minutes and tests quickly in a free-space configuration.”“We received customized full service and support. This was one of several projects with IZAK, and the team was professional and delivered on time.” Moshe Aizler, Testing Development Manager, Automation & Control Solutions, MKS InstrumentsFrequently asked questions
QWhat does LED functionality mean?
QHow is LED functionality tested?
QCan an LED tester be added to an existing test system?
Tzachi Sabati
CEO, IZAK Scientific
Physicist specializing in photonics and quantum technologies, with deep expertise in quantum sensors and advanced optical systems. Leads the Advanced Quantum Lab course at the Technion, bridging academic excellence with industry innovation. At IZAK Scientific, provides cutting-edge photonics-based solutions, developing customized inspection and sensing systems for R&D and production. Passionate about advancing quantum sensing applications and integrating novel technologies to meet industry needs.
