Edward Tang | Avegant Corp.: Why is one watt the absolute thermal and power limit for consumer AR glasses?
01:56 - 03:19
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Summary of the clip:
Why is one watt the absolute thermal and power limit for consumer AR glasses?
Data and research show that consumer AR glasses cannot exceed about 50 grams if they are to be all-day wearable. Above 50 grams, the device becomes a short-term use product, worn for an hour or two, and loses the ability to replace your everyday glasses. Hitting that number is incredibly difficult given all the components that must go into the glasses.
The second constraint is the thermal budget. Devices cannot get too hot: too hot means discomfort or, worse, a safety issue that may burn your skin. Typically you want to stay below 50 degrees, and ideally below about 43 degrees, for the device to be safe and comfortable. Combined with the 50-gram limit, this creates a serious thermal dissipation challenge.
With a 50-gram limit, you cannot put fans in these devices, and you can't really put heat sinks in them either: they are too small and too light, and there is no way to get airflow through the system. That is where the one watt number comes from, as about the maximum thermal dissipation limit achievable through a pair of glasses while keeping them small, lightweight and consumer-friendly.
In this short video, you can learn:
* All-day wearable consumer AR glasses must not exceed about 50 grams, or they degrade into one-to-two-hour short-term use devices.
* Device temperatures must stay below 50 degrees, and ideally below about 43 degrees, to remain comfortable and avoid burning skin.
* Because a 50-gram device cannot use fans, heat sinks or airflow, roughly one watt is its practical thermal dissipation ceiling.
📋 **Clip Abstract** Consumer AR glasses face two hard ceilings: about 50 grams of mass for all-day wear, and skin-safe surface temperatures below 50 degrees, ideally about 43 degrees. Because a device that small and light cannot host fans, heat sinks or airflow, those limits converge on roughly one watt of maximum thermal dissipation.
About the speaker:
* Speaker: Edward Tang
* Company: Avegant Corp.
* Event: Eindhoven 2026
* Location: High Tech Campus, Eindhoven
#50GramWeightLimit, #ThermalDissipationCeiling, #PassiveCooling, #SkinTemperatureLimit, #AugmentedReality, #SmartGlasses
This is a highlight of the presentation:
Power is all you need !
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08:29 - 10:16
How does average pixel level (APL) expose color microLED power limits versus LCOS?
How does average pixel level (APL) expose color microLED power limits versus LCOS?
The graph tracks display power consumption against average pixel level. Color microLED systems, because of inefficiencies, thermal efficiencies, EQ issues and etendue problems, can really only operate at low APLs, typically well under 10% APL if they must stay within the right power constraint or power budget. LCOS today is efficient enough to operate across all APLs within the needed power budget, which helps explain why companies outside China, such as Meta or Snap, already ship LCOS displays.
Traditional LCOS systems do not benefit from low APL in the same way. They illuminate the entire image very uniformly, so power is pretty much flat with content. That creates an intersection point between the two display technologies on the power-versus-APL graph. This power intersection point typically happens under about 10% APL. Below that level, color microLED power constraints are severe; above it, LCOS can keep operating within the required budget without APL limitations.
The good news is that efficient LCOS technology is already a shipping answer. For a high-resolution, full-color display with no APL limitations, LCOS is available today. It avoids the low-APL restriction that constrains color microLED light engines under the power budget. That makes LCOS the practical choice when small, lightweight glasses require performance across content. This is not a future promise but an existing display path for full-color images.
In this short video, you can learn:
* Color microLED systems can typically operate only well under 10% APL to stay inside the required power budget.
* LCOS operates across all APLs within the needed power budget and delivers full-color images with no APL limitations.
* The power intersection between LCOS and color microLED typically happens under about 10% APL, and Meta and Snap already ship LCOS displays.
📋 **Clip Abstract** Average pixel level determines whether a display stays inside the power budget: color microLED systems are limited to low APLs, typically well under 10%, due to inefficiencies, thermal efficiencies, EQ issues and etendue problems. LCOS operates across all APLs, and companies outside China such as Meta or Snap already ship LCOS displays for full-color images with no APL limitations.
About the speaker:
* Speaker: Edward Tang
* Company: Avegant Corp.
* Event: Eindhoven 2026
* Location: High Tech Campus, Eindhoven
#AveragePixelLevel, #LCOSDisplays, #ColorMicroLED, #PowerIntersection, #ARDisplays, #LightEngines
20:47 - 22:11
Why is shrinking LCOS pixel sizes below three microns critical for achieving larger fields of view in AR?
Why is shrinking LCOS pixel sizes below three microns critical for achieving larger fields of view in AR?
Today AR is mostly limited to small fields of view, 20 to 30 degrees. That limit comes from power, primarily from wavelength efficiency. Customers are already demanding larger fields of view: how do we get to 50, 60, 70 degrees? If you do not want glasses to get larger, you must shrink pixel size. LCOS has the ability to shrink pixel size.
LCOS has standardized around three microns, but people are already moving to two microns, 2.8 microns, two and a half, two microns, and even smaller. That really opens up the ability to make large field of view small glasses. Shrinking pixels is how you get larger fields of view without making the glasses larger. The display must scale down at the pixel level while the field of view scales up.
MicroLEDs, by contrast, already struggle with quantum efficiency even at two, three, four microns. Getting down to even smaller pixel sizes is exponentially more difficult for them. That is where LCOS pixel shrinkage has a clear advantage for large field of view small glasses. The road below three microns is critical for AR field of view growth.
In this short video, you can learn:
* AR displays today are limited to 20 to 30 degree fields of view by power, primarily wavelength efficiency.
* LCOS has standardized around three microns but is moving toward 2.8, 2.5, two microns, and even smaller.
* MicroLEDs already struggle with quantum efficiency at two, three, and four microns, and smaller pixels are exponentially more difficult.
📋 **Clip Abstract** The clip explains that AR's current 20 to 30 degree field of view is constrained by power, mainly wavelength efficiency. Shrinking LCOS pixels from a three-micron standard toward two microns and below enables 50 to 70 degree fields of view in small glasses, while microLEDs face quantum-efficiency difficulty at 2 to 4 microns and below.
About the speaker:
* Speaker: Edward Tang
* Company: Avegant Corp.
* Event: Eindhoven 2026
* Location: High Tech Campus, Eindhoven
#LCOS, #MicroLED, #WavelengthEfficiency, #QuantumEfficiency, #AROptics, #NearEyeDisplays
12:22 - 14:44
How can shrinking the light engine's pupil size more than double waveguide coupling efficiency?
How can shrinking the light engine's pupil size more than double waveguide coupling efficiency?
Pupil size is a really important knob. Light engine efficiency and waveguide efficiency are usually assessed separately, yet what actually matters is milliwatts to the glasses to nits to the eye. That means treating the light engine and the waveguide together, as one system, and accounting for the losses at the interface between them. Co-optimising that interface is where the gains hide.
The input to a waveguide is not uniformly efficient. One side is very inefficient, because light has to travel multiple bounces through that input pupil, and every time it touches it, a lot of light is lost. Other areas are highly efficient: light enters the input pupil and couples immediately into the waveguide without secondary interactions. Shrinking the pupil lets the engine target the efficient regions.
A typical microLED system has a pupil of three and a half to four millimetres. Assuming about 1,000 nits per lumen at that pupil size, simply reducing pupil size lifts waveguide efficiency by 50%; moving from unpolarised to polarised light adds another 50%. That means more than doubling waveguide efficiency. And a smaller pupil allows a thinner waveguide, cutting weight and freeing budget for lighter glasses or more battery.
In this short video, you can learn:
* Reducing pupil size raises diffractive waveguide coupling efficiency by 50%, and polarised light versus unpolarised contributes another 50%.
* Waveguide input pupils are non-uniform: one side loses light to repeated bounces while other regions couple immediately with no secondary interactions.
* A smaller light engine pupil also permits a thinner waveguide, reducing weight and leaving budget for lighter glasses or more battery.
📋 **Clip Abstract** Pupil size controls how much light the light engine actually delivers to the eye, because waveguide input pupils are unevenly efficient. Co-optimising the light engine pupil with the diffractive waveguide — shrinking it from three and a half to four millimetres and polarising the light — can more than double waveguide efficiency while thinning the waveguide.
About the speaker:
* Speaker: Edward Tang
* Company: Avegant Corp.
* Event: Eindhoven 2026
* Location: High Tech Campus, Eindhoven
#WaveguideCouplingEfficiency, #PupilSizeReduction, #DiffractiveWaveguides, #MicroLEDLightEngine, #AROptics, #NearEyeDisplays