I wanna to measure an unknown LED electro-optical parameters specially intensity and dominant wavelength and Spatial Distribution.
Which way is best? using a photodetector and tunable filter in visible range?
or using colour sensors such as TCS3200 and TSL200?
or other methods?
tolerance between +/- 20 nm is negligible for our products.
Please state your experience.
tanks so much ...
You can use an optical fibre to collect light at many angles you desire.
The other end of the fibre may be connected to a CCD-spectrometer in the visible spectra.
You could use an adequate set-up to collect light from a LED using a fiber optic adequate to the wavelength range to be tested (SMA connectors in both extremes might be suitable but some care would be required on the LED end of the fiber to ensure a stable reading). The other end of the fiber could be connected to a CCD-miniature spectrometer through a SMA connector. This type of spectrometer is a bit expensive but it would have the advantage of providing the specific LED spectra.
Depends pretty much on accuracy and resolution (spatial and spectral) you need.
Most simple setup would be consisting of optical power meter, a set of narrow-band filters and translation stage with +-90 degree rotation. The LED under test is mounted onto this translation stage so that you can rotate it left and right keeping the emitting surface at the same point. At 0 degree orientation the LED should be directed straight to the optical power meter sensor.
OPM readings vs. rotation angle will give you angular distribution of emitted light, at least for one LED axis. Most likely this distribution has axial symmetry - you can verify this by rotating LED in its socket and repeating the measurements.
For spectral distribution, use narrow-band filters positioned in front of the OPM sensor.
Thanks everyone for helpful comments, Can you explain how to measure the light spectrum with very simple tools !!!? in other words I wanna to know which parameters in OPTICAL POWER METER for our purpose are important?!!
Actually, I have a little data about suitable power meters,
can i simulate this device(OPM) with simple PIN photodetectors? or i have to buy such a device?!! :(((
please explain mechanical setup for this purpose,
thank you so much,
Optical Power meter is simple enough tool, hardly any more complicated than digital multimeter. Typically, it consists of two parts - a meter itself that displays the power, and a remote light sensor connected to the meter with a cable. You can position the sensor anywhere you need. On a meter, you only need to set wavelength you're measuring at.
And you don't have to buy it - I'm pretty sure that ThorLABS or Newport power meters can be rented. Or even borrowed.
I don't think you can simulate OPM or use off-the-shelf PIN photodiode as a substitution. The sensor that comes with any OPM is precalibrated (with each sensor having individual calibration!), that's what makes it a measurement tool and not just light detector. If you don't know in advance spectral response of the photodiode - you can't get reliable results.
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