An essential constituent of the TERALED setup
for combined measurements is MicReD's T3Ster® - the thermal transient tester equipment. This state-of-the-art
thermal tester measures thermal transients according to the
JEDEC JESD51-1 standard, in real-time, with 1µs time
resolution. The structure functions derived from the transients allow a non-destructive
structural analysis.
A 300 mm diameter integrating sphere hosts the temperature
stabilized DUT fixture, the reference LED and a radiometric
detector or a detector head with a bank of different filters.
The available filters are: equispectral, V(l),
V'(l), X and Z. The photometric
detectors are matched to the CIE V(l)
function with 1.5% accuracy. The optical configuration
of the TERALED system complies with all recommendations
of CIE regarding LED measurements.
When combined optical/thermal measurements are performed,
the T3Ster® equipment is used to provide powering for the LED under test.
The control of the thermal measurements and the evaluation of
the thermal transients is performed by the T3Ster software,
while the measurement sequences required for the photometric
and radiometric characterization are performed by the TERALED software. The measured emitted optical power then is considered
by the T3Ster software when calculating the thermal metrics
of the LED under test.
Temperature controlled
fixture
Part number: MIC-TERAFX10
TEMPERATURE
CONTROLLED DUT FIXTURE
Peltier-based device
Connects to the 60mm DUT port of the sphere
Control
by the TERALED electronics
Major characteristics:
• 60
mm diameter
• 40x40
mm2 mounting area
• 15..90
°C temperature range
• power
sinking capability: max. 10 W
Supported
applications
Cold-plate during thermal measurements
Thermostat
for optical measurements
Device calibrator (K-factor identification)
Allows Ftot(T)
and Flum(T) measurements
The DUT connections (4 wires: current force +/- and voltage sensing
+/-) are fed through the fixture. At the outer side connection to
the TERALED electronics (stand-alone optical measurement
mode) or to the power driving module of the T3Ster® equipment can be established by simple adaptors supplied
with the DUT fixture.
The temperature controlled DUT LED fixture fits into the corresponding 60mm port of the TERALEDintegrating sphere. The temperature controlled DUT LED fixture is a mandatory part
of the TERALED system.
Mechanical attachment of the DUT LED to the temperature
controlled surface should ensure good thermal contact. It is also
very important that the attaching mechanism must not obstruct the
light from the DUT LED and it should have minimal self-absorption.
A demo LED with a demo attaching mechanism is provided with the temperature
controlled fixture.
High precision detector
head
Part number: IPR-TERADET
The detector head used in TERALED is compatible
with Inphora's IPR-DES series detectors' 25mm
geometry. It fits into the detector port of the TERALEDsphere using a 25/60mm adaptor.
In a TERALED setup either a plain detector (with uniform
spectral response) is installed - serving as a radiometric detector,
or a filter bank is inserted between the sphere and the detector head.
The filter bank is computer controlled (via the TERALED control electronics) and can host up to 6 filters for the measurement
of the radiometric and luminous fluxes (with V(l)
or V'(l) characteristics) and for the measurement
of the X and Z chromacity coordinates.
The TERALED detector head is based on
a silicon photovoltaic cell which is hosted in a temperature controlled
chamber. This, completed with the high precision filter design and
manufacturing used also in other Inphora detectors, provides a measurement
accuracy of 1.5%.
The voltage supply and for the temperature stabilization
circuitry of the detector head is provided by the TERALED control electronics. In its stabilized state the detector head sends
a READY signal to the TERALED electronics - indicating
that measurements can be started. The output signal of the detector
head is received and digitalized also by the control electronics.
This way automated measurement sequences can be carried out by the TERALED measurement control software.
The detector head is a mandatory system component.
The computer-controlled filter bank (part number: IPR-TERFILT) is
optional. If no filter bank is ordered, the detector head is shipped
as a radiometric detector.
Reference LED
The TERALED sphere is shipped after a
detailed calibration procedure is performed using
5 different standard LEDs of Inphora (red, green, yellow, blue, white).
Thanks to this pre-calibration a simplified calibration procedure
is sufficient for the actual measurements using just a white reference
LED serving as an auxiliary lamp to account for the self-absorption
of the DUT LED.
Part number: IPR-TERAREF
The TERALED system is shipped with a temperature
and current stabilized white reference LED. The diameter of
the reference LED is 25mm and it fits directly into the 25mm
reference LED port of the TERALEDsphere.
The voltage supply of the stabilization circuitry is provided by
the TERALED control electronics. Also, the TERALED electronics switches on/off the reference LED and receives its READY
signal indicating its stable state. The TERALED white
reference LED is compatible with Inphora's IPR-DES series standard
LEDs.
The reference LED is a mandatory part of the TERALED system.
Integrating
sphere
TERALED setup
General description:
The major system component of the TERALED setup is
a 300mm integrating sphere. It is equipped
with 3 ports: two 60mm ports are aimed
for the temperature controlled DUT LED fixture and for the detector head attached to a filter
bank. A 25mm port hosts the white reference
LED and another 25mm port is aimed
for a fiber optics output to enable an easy connection of third
party tools like a CCD-based spectrometer.
The TERALED integrating sphere fits in size with the TERALED control electronics. It can be safely placed on top of the box of
the control electronics. Cable connections to the DUT LED fixture,
detector head and filter bank and to the reference LED are provided.
• Sphere
diameter: 300 mm
• Total
height: 420
mm
• Total
width: 385
mm
Port locations and diameters:
• at
0° 25mm
port for reference LED
• at 90° 60mm
port for DUT fixture
• at
180° 60mm port
for detector
• at
200° 25mm port
for fiber optics
Port style: knife-edge
Ports are compatible with
Inphora's IPR-DES series detectors and standard
LEDs.
Symbolic diagram
- may differ from actual
product.
Calibration:
The sphere is color calibrated in our works with 5 standard LEDs (blue,
green, red, amber, white). Calibration constants are shipped with
the TERALED software. Recalibration in max. every 2
years is needed (if used in a clean environment). Automatic software
warning for the need of recalibration of the sphere is provided by
the software. In the field calibration for self-absorption is done
with a single white reference LED. The TERALED software
performs this calibration automatically. The white reference LED needs
recalibration in every 2 years or 100 burning hours (whichever is
shorter). Calibration kit can be purchased separately.
Symbolic diagram - may differ from actual
product.
Standard
accessories:
• 60/25
mm adaptor for the detector port
• port
cover caps
• connector
cables to the control electronics
Control electronics
The TERALED control electronics is responsible
for the temperature control of the DUT LED fixture, provides power
supply for the temperature and current stabilized reference LED as
well as for the temperature stabilized detector head. If installed,
the automated filter bank obtains its power and control also from
the control electronics. The TERALED electronics switches
on and off the reference LED, receives the output signal with its
high precision, auto-range detector current input amplifier and provides
a digital reading of the measured photosignal. The filters installed
in the filter bank are moved in front of the detector head with a
stepping motor.
TERALED control unit
The front panel of the control electronics provides visual feedback about the status of all the system components:
the stable state of the reference LED, the detector and the filter
in use is indicated by small LED signals.
The control electronics connects to any computer via
its USB interface. The measurement control software runs on
Windows® 2000/XP operating systems.
To allow stand-alone measurements, the TERALED electronics can be used to provide bias current for the LED under
test. A current up to 2 A can be programmed. The stability of the
LED is monitored by the control electronics by measuring its forward
voltage.
When combined thermal and radiometric/photometric
measurements are performed, the powering of the DUT LED is provided
by the T3Ster® equipment.
In either case the control electronics ensures a total
switching off of the DUT LED when it is necessary (e.g. during calibration
with the reference LED).
The whole system is supervised by the TERALED software running on the measurement control computer. The software
checks if all the required cards of the TERALED electronics
are installed and are functional. The software also checks if the
detector head, the filter bank, the reference LED and the temperature
controlled DUT fixture are really attached to the system.
60mm port of the TERALED 
