Kai Hohmann | Aumovio: What real-world trade-offs emerge at 7,000 cd/m² with 70% transparent MicroLED automotive display?
11:44 - 14:06
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What real-world trade-offs emerge at 7,000 cd/m² with 70% transparent MicroLED automotive display?
The transparent microLED demo targets automotive designs that exploit high luminance and high transmission. Its stated specification is more than 50% transparency and more than 1,500 cd/m² luminance, with 3,000 cd/m² or more considered better because OLED has a limitation there. The tough discussion is not only resolution but uniformity, color space and pixel failures, which experts debate as potentially observable by the driver.
For the demo, transmission measured almost 70%, which is very good compared to OLED. It was an AR coating on one side. If the microLED is optically bonded on the cover glass with an AR coating on the backside, and the cover glass has an AR coating, the expectation is to come over 70%.
The demo's white luminance reaches almost 7,000 cd/m². Its luminance distribution shows only the red chip has a certain Lambertian or regular characteristic; the blue and green chips, and then white, are more toward the bottom side, probably from how the LEDs emit light. Another issue is that 8.4% red is very low, feeding the color-space discussion. A typical OLED display, by contrast, is perfectly centered in white.
In this short video, you can learn:
* The transparent microLED demo measured almost 70% transmission with an AR coating on one side, and further optical bonding plus AR coatings could exceed 70%.
* White luminance reached almost 7,000 cd/m², but red was only 8.4%, and blue, green and white distributions shifted toward the bottom side.
* Automotive specifications debate more than 50% transparency, more than 1,500 cd/m² luminance, and issues including uniformity, color space, pixel failures and resolution.
📋 **Clip Abstract** A transparent microLED automotive demo combines high transmission with high luminance, measuring almost 70% transmission and nearly 7,000 cd/m² white luminance. Its trade-offs include blue, green and white emission shifted toward the bottom, only 8.4% red, and open specification debates around uniformity, color space, pixel failures and resolution.
About the speaker:
* Speaker: Kai Hohmann
* Company: Aumovio
* Event: Eindhoven 2026
* Location: High Tech Campus, Eindhoven
#TransparentMicroLED, #ARCoating, #OpticalBonding, #LuminanceDistribution, #AutomotiveDisplays, #MicroLEDDisplays
This is a highlight of the presentation:
Advances in MicroLED for Automotive Applications
More Highlights from the same talk.
07:46 - 09:27
Why are MicroLEDs on silicon backplanes ill-suited for automotive head-up displays despite their high resolution?
Why are MicroLEDs on silicon backplanes ill-suited for automotive head-up displays despite their high resolution?
MicroLED on silicon or CMOS backplanes delivers the highest resolution and uses a full semiconductor process, but it is size limited and too expensive to scale up. It is dedicated to AR glasses and heads-up displays. For head-up displays, two questions decide viability: is the light collimated, and can a micro lens array be integrated? If yes, we continue; if no, it is difficult because too much stray light is in the HUD.
If the LEDs are Lambertian emitters, every stray light in the head-up display decreases contrast and the user experience. That is the core problem for HUDs. MicroLED on TFT glass instead uses thin-film transistors to drive the Micro LEDs. It is a standard LCD process running in huge factories in Asia, so in practice there is basically no size limitation.
A big display from left to right can have 30 million LEDs. How many wafers that requires depends on the chosen approach, so deployment will probably start more with smaller sizes. Candidate applications include direct-view displays, panorama head-up displays, transparent displays, or those into visible displays, because there we need high brightness. MicroLED on TFT glass drives that.
In this short video, you can learn:
* MicroLED on silicon or CMOS backplanes has the highest resolution but is size limited and too expensive to scale up.
* For head-up displays, collimated light or a micro lens array is required, because Lambertian emitters and stray light reduce contrast and user experience.
* MicroLED on TFT glass uses thin-film transistors in a standard LCD process with basically no size limitation, and a big display can contain 30 million LEDs.
📋 **Clip Abstract** MicroLED on silicon or CMOS backplanes offers the highest resolution but is size limited, costly to scale, and dedicated to AR glasses and head-up displays. For HUDs, the key questions are collimated light and micro lens array integration, because Lambertian emitters and stray light reduce contrast; TFT glass instead uses thin-film transistors in a standard LCD process with basically no size limitation.
About the speaker:
* Speaker: Kai Hohmann
* Company: Aumovio
* Event: Eindhoven 2026
* Location: High Tech Campus, Eindhoven
#CMOSBackplanes, #TFTGlassBackplanes, #MicroLensArray, #LambertianEmitters, #MicroLEDDisplays, #AutomotiveHUDs
14:21 - 15:43
Why does correcting the white point of an automotive MicroLED display cause a massive 2.5x penalty in brightness?
Why does correcting the white point of an automotive MicroLED display cause a massive 2.5x penalty in brightness?
Color-space measurements show red, green, and blue at the edge of the curve, but white appears more cyan because there is too little red. An adjusted OLED matches the white specification after adjustment. If the MicroLED is adjusted to the OLED white space, the result is a loss of a 2.5 factor in brightness. Automotive therefore needs a good red or a more efficient red as the drawback.
White uniformity is another automotive constraint. A measurement shows the requirement is 80%, but the result is below 30. The behavior looks like a voltage drop or current drop over the MicroLED. This can be addressed by design, but it was the status at that time. Product designers have to work on it. OLED, by comparison, is very good.
Two metrics define the automotive comparison. First, the MicroLED white point is more cyan, with too little red; correcting it to OLED white space costs a 2.5 factor of brightness, so a good or more efficient red is needed. Second, white uniformity must reach 80%, yet the measurement is below 30, showing a voltage or current drop over the MicroLED. Design changes are required, while OLED white adjustment and uniformity are very good.
In this short video, you can learn:
* Adjusting MicroLED white to OLED white space loses a 2.5 factor of brightness because the white point is too cyan and red-limited.
* MicroLED white uniformity measured below 30 against an 80% requirement, with behavior resembling a voltage or current drop over the MicroLED.
* OLED is adjusted to match the white specification and shows very good uniformity, while a good or more efficient red is needed for automotive MicroLED.
📋 **Clip Abstract** Automotive MicroLED color-space data show red, green, and blue at the curve edge, but white is more cyan from too little red; correcting it to OLED white space costs a 2.5 factor of brightness. White uniformity measures below 30 against an 80% requirement and appears linked to voltage or current drop over the MicroLED, while OLED white adjustment and uniformity are very good.
About the speaker:
* Speaker: Kai Hohmann
* Company: Aumovio
* Event: Eindhoven 2026
* Location: High Tech Campus, Eindhoven
#MicroLEDWhitePoint, #BrightnessPenalty, #WhiteUniformity, #RedEfficiency, #AutomotiveDisplays, #MicroLEDDisplays
09:27 - 11:28
Can micro-CMOS drivers on passive substrates compete with LTPS TFT backplanes for mid-sized automotive displays?
Can micro-CMOS drivers on passive substrates compete with LTPS TFT backplanes for mid-sized automotive displays?
Micro-CMOS drivers use a CMOS driver chip controlling multiple LEDs. That also has the ability to use a passive backplane with semiconductors equipped on it, so no LTPS backplane. It is dedicated for medium-sized applications, also for PHAT, and hopefully for transparent displays. For automotive it is still new and remains to be checked. This is one of the two central options being focused on.
Micro LED on TFT glass is very important. It is the standard display process: a batch process, completely processed, with the backplane processed in one huge mother glass. LED attachment differs from OLED. Before, the LTPS backplane is the same process, but different circuits, and then the LED attachment. Many suppliers are already focusing on it. Standard micro LED on PCBs reaches only 40 to 60 PPI, so it is probably not relevant for automotive.
The alternative micro-CMOS route is a different process compared to standard TFT. It is more a die bonding process on the passive substrate. Technical questions still need solving for driving frequency, bandwidth, color space and dimming concepts. For automotive, the central question is whether this can compete with LTPS and its huge process, yes or no. That is the next thing being checked.
In this short video, you can learn:
* Micro-CMOS drivers place a CMOS driver chip controlling multiple LEDs on a passive substrate, avoiding an LTPS backplane.
* Micro LED on TFT glass uses a batch process with the LTPS backplane processed in one huge mother glass, but LED attachment differs from OLED.
* Standard micro LED on PCBs reaches only 40 to 60 PPI, making it probably not relevant for automotive, while micro-CMOS still faces driving frequency, bandwidth, color space and dimming questions.
📋 **Clip Abstract** The clip contrasts micro LED on TFT glass, the standard batch process with an LTPS backplane in one huge mother glass, against micro-CMOS drivers on a passive substrate. It identifies unresolved automotive questions for micro-CMOS—driving frequency, bandwidth, color space and dimming concepts—and asks whether it can compete with LTPS, while PCB-based micro LED at 40 to 60 PPI is likely irrelevant.
About the speaker:
* Speaker: Kai Hohmann
* Company: Aumovio
* Event: Eindhoven 2026
* Location: High Tech Campus, Eindhoven
#MicroCMOSDrivers, #LTPSBackplane, #PassiveSubstrate, #DimmingConcepts, #MicroLEDDisplays, #AutomotiveDisplays