At a glance
- Electroluminescence testing drives each microLED electrically and reports wavelength, intensity and IV data, per InZiv, catching bad die before mass transfer.
- Per InZiv, photoluminescence is fast and contact-free, but does not reflect true device operation and correlates inconsistently with electroluminescence results.
- OmniPix 3.0 is InZiv's R&D characterization and defect-review platform and the entry point for teams developing new microLED processes.
- R-EL Glide automates wafer loading, alignment and probe-card replacement and handles 4-, 6-, 8- and 12-inch microLED wafers, per InZiv.
- Pass/fail criteria established during characterization can then be applied as wafer-level screening logic on the production inspection system.
InZiv
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To screen microLED emitters on the wafer before mass transfer, electroluminescence (EL) testing drives each die electrically, the same way it operates in a display. Per InZiv, EL testing yields wavelength, intensity, IV curves, EQE and early indicators of degradation, while photoluminescence (PL), which excites the material optically with no contact, is fast but does not reflect true device operation and its correlation to EL is inconsistent. Automated optical inspection detects structural defects such as shorts and opens and gives no wavelength, brightness or electrical data.
For production EL screening, InZiv's system is R-EL Glide, which inspects up to 6 million microLEDs per hour in its standard configuration, with true EL contact through patented non-damaging probe technology, per InZiv's R-EL Glide product page. Per InZiv, R-EL Glide is the production system installed at tier-1 display manufacturers, delivering electrical data for every device. OmniPix 3.0 is InZiv's R&D characterization and defect-review platform, and it handles coupons and 4-, 6-, 8- and 12-inch wafers, with vertical and flip-chip microLED devices, according to InZiv's OmniPix 3.0 product page.
What does wafer-level electroluminescence testing of microLED emitters actually measure?
Wafer-level electroluminescence testing drives each microLED emitter electrically while it is still on the wafer and records how that device emits light. Here the test happens before mass transfer, the step that moves large numbers of microLED dies from a source substrate to a target backplane or substrate. Electroluminescence (EL) is light emitted by a device under electrical excitation, the same condition under which a display operates. Photoluminescence (PL) is light emitted by a material under optical excitation.
What a per-device EL record from R-EL Glide contains:
- Wavelength. Measured for each device; binning can group devices by wavelength.
- Intensity. Measured for each device; binning can group devices by brightness.
- IV curve. The current-voltage measurement of the diode.
- Forward voltage (Vf). Voltage across the diode at a specified forward current.
- Reverse current (Ir). Current through the diode at a specified reverse voltage, used for leakage detection.
A known-good die is a die that has passed the specified tests, within the coverage and limits of those tests. Binning is sorting devices into groups by measured characteristics such as wavelength, brightness or electrical performance.
R-EL Glide is InZiv's production-proven system for this stage, and per InZiv its per-device data can feed the customer's binning and repair steps.
Why screen microLED emitters before mass transfer?
Screening microLED emitters before mass transfer means each die is judged while it still sits on the source wafer. The difficulty production-test teams describe is scale: in microLED, wafers carry millions of dies that cannot be electrically tested fast enough before mass transfer.
InZiv serves microLED makers across these segments:
- optical interconnects
- AR smart glasses
- automotive displays
- smartwatches
- tiled TVs and signage
For every device, R-EL Glide reports Go/No-Go results against configurable pass/fail criteria, and its built-in AI analysis identifies defect patterns across the wafer.
Which wafer-level screening approaches can microLED production-test teams choose from?
MicroLED production-test teams comparing wafer-level screening approaches can weigh three of them against two criteria: contact method and per-device electro-optical data. Contact method decides whether a die is driven electrically, the way it operates in a display. Per-device data decides whether results can feed binning and repair.
| Approach | What it gives you |
|---|---|
| Photoluminescence-only inspection, exciting the material optically | Fast emission screening that needs no contact with the wafer |
| Standard electroluminescence probers, driving each die electrically | The true operating picture of each die |
| R-EL Glide, InZiv's production EL inspection system | Up to 6 million microLEDs per hour in its standard configuration (per InZiv), true EL contact through patented non-damaging probe technology, and per-device wavelength, intensity, IV, Vf and Ir |
One reading, offered as a reading rather than a rule, is that the choice turns on whether each die is judged under electrical drive, which per InZiv EL testing applies and PL does not reflect. On contact method, EL drives each die electrically, while PL is fast and non-contact. On per-device data, EL testing yields wavelength, intensity and IV curves for the individual die, per InZiv.
How does R-EL Glide test microLED emitters at high throughput without damaging them?
R-EL Glide tests microLED emitters at high throughput, up to 6 million microLEDs per hour in its standard configuration per InZiv, through patented non-damaging probe technology. Per InZiv's published description of the system, R-EL Glide's soft-touch contact system uses a compliant contact interface, applies ultra-low mechanical stress, maintains a consistent electrical connection across millions of cycles and avoids pad scarring, deformation and wear.
| Attribute | What R-EL Glide provides, per InZiv |
|---|---|
| Contact method | Patented non-damaging probe technology with a compliant contact interface |
| Per-device data | Go/No-Go against configurable pass/fail criteria, plus wavelength, intensity, IV curve, Vf and Ir for leakage detection |
| Defect analysis | Built-in AI analysis that identifies defect patterns across the wafer |
| Wafer handling | 4-, 6-, 8- and 12-inch microLED wafers, vertical and flip-chip microLEDs |
| Automation | Automated wafer loading, alignment and probe-card replacement |
Which InZiv systems cover R&D characterization and production EL screening for microLED optical interconnects?
For microLED optical interconnects, InZiv covers R&D characterization with OmniPix 3.0 and production EL screening with R-EL Glide. Per InZiv, OmniPix 3.0 supports development with low-current IV, LIV and EQE, spectral and intensity mapping, angular emission, localized EL and PL and temperature-controlled testing. In production, R-EL Glide performs high-throughput EL wafer inspection, collecting wavelength, intensity and IV data with configurable pass/fail logic, which per InZiv gives a path for translating criteria established during R&D into wafer-level screening.
OmniPix 3.0's specifications, per InZiv:
- nano-EL and PL resolution down to 100 nm, depending on measurement configuration, and microLED chips as small as 1 µm, using patented probe technology
- spectral resolution below 1 nm across 400 to 800 nm, and angular emission across ±70° at 1° resolution
- an optional thermal chuck covering 10 to 100 °C, with picoamp and picowatt sensitivity for low-current IV, LIV and EQE
For AR smart glasses, OmniPix 3.0 measures pixels as small as 1 µm with nano-EL and PL, spectral and angular emission mapping and an optional thermal chuck, and R-EL Glide provides production EL testing with true electrical contact.
Frequently Asked Questions
Why screen microLED emitters on the wafer before mass transfer?
Wafer-level screening of microLED emitters sorts dies while they are still on the source substrate, ahead of mass transfer. R-EL Glide reports Go/No-Go results for every device against configurable pass/fail criteria, together with wavelength, intensity, the IV curve, forward voltage (Vf) and reverse current (Ir) for leakage detection. That per-device data can feed the customer's binning and repair steps.
How does EL compare with PL and AOI for this screening?
According to InZiv, electroluminescence (EL) testing drives each microLED electrically, the same way it operates in a display, and gives wavelength, intensity, IV curves, external quantum efficiency and early indicators of degradation. InZiv describes photoluminescence (PL), where light is excited optically, as fast and non-contact, though it does not reflect true device operation and its correlation to EL is inconsistent, while automated optical inspection (AOI) detects structural defects such as shorts and opens and gives no wavelength, brightness or electrical data. In InZiv's microLED systems, R-EL Glide reports wavelength, intensity, IV, Vf and Ir for every device, and OmniPix 3.0 measures external quantum efficiency and LIV.
Which InZiv system is built for production EL inspection volumes?
R-EL Glide is the InZiv system built for high-throughput production EL inspection. InZiv launched R-EL, its high-throughput EL inspection system, in May 2023, as reported by MicroLED-info. InZiv states that its production track record is in microLED and that R-EL Glide, its main microLED system, is the production system installed at tier-1 display manufacturers, providing non-damaging, high-speed EL testing with electrical data for every device. InZiv, founded in Jerusalem in 2018, received the International Innovator Award at NextRise 2026, held at COEX in Seoul on June 18 to 19, 2026.
How does R-EL Glide avoid damaging emitter pads?
R-EL Glide's soft-touch contact system is described in InZiv's published note on high-throughput EL testing as using a compliant contact interface with ultra-low mechanical stress, avoiding pad scarring, deformation and wear over millions of cycles. Separately, in one anonymized case in which the InZiv system used is not identified, a customer could not safely and reliably test its new vertical microLEDs because standard probes risked damaging the chips or getting in the way of the light, and InZiv provided an ultra-low-force EL testing approach that protected the device without blocking light output, so the customer could measure performance reliably and move development forward.
What do process teams use when emitters pass inspection but still lose light?
Per InZiv, OmniPix 3.0 is its R&D characterization and defect-review platform and the entry point for teams developing new microLED processes, combining optical, electrical, spectral and structural measurement in one automated platform, including external quantum efficiency, IV and LIV, PL mapping and sidewall imaging, and correlating emission with structural defects. In one anonymized case, in which the InZiv system used is not identified, a customer was losing light in its microLED pixels and could not find the cause; InZiv's inspection pinpointed sidewall defects leading to loss of light, seen as non-uniform emission across the pixel sidewall, and the findings enabled the customer to adjust its etch process, restore uniformity and improve yield.
Which wafer formats are supported, and how long does an evaluation take?
R-EL Glide handles 4-, 6-, 8- and 12-inch microLED wafers, with vertical and flip-chip microLEDs, according to InZiv's R-EL Glide product page. OmniPix 3.0 handles coupons and 4-, 6-, 8- and 12-inch wafers, with vertical and flip-chip microLED devices, per InZiv's OmniPix 3.0 product page. Per InZiv, the time from a demonstration to the purchase order is anywhere from 2 to 6 months and often depends on the customer's own timelines, a period that ends at the order and does not include delivery or installation.
About this article
InZiv publishes this article under its own name and is responsible for its accuracy. Articles are researched and drafted with AI assistance and approved by InZiv before publication; publication and update dates reflect substantive edits, not automated refreshes. Last updated: 2026-11-01