Uwe Vogel | Fraunhofer IPMS: Your AR glasses' battery life is terrible. Is the backplane to blame?
00:06:30 - 00:08:43
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Summary of the clip:
Your AR glasses' battery life is terrible. Is the backplane to blame?
This clip contrasts two fundamentally different microdisplay driving architectures: frame-controlled and memory-based. A conventional frame-controlled display continuously scans and updates all pixels, requiring a constant high-bandwidth video stream and a power-hungry controller, resulting in a backplane power consumption of 150-200 milliwatts for a typical SVGA display.
The memory-based approach revolutionizes power consumption by using an event-based data transfer. Pixels are only updated when their content changes, and the image is stored locally within the pixel circuitry. This allows for a "zero hertz" frame rate for static images, where the backplane power drops to a mere 20 microwatts, an almost negligible amount.
Even when displaying video-rate content, the memory-based backplane consumes only about 1 milliwatt, a reduction of over 99% compared to the frame-based architecture. In this mode, the display's total power consumption is almost entirely determined by the light-emitting OLEDs themselves, not the underlying silicon. This architectural shift is critical for enabling truly all-day wearable devices.
In this short video, you can learn:
* The difference between frame-controlled and memory-based (memory-in-pixel) driving schemes.
* How memory-in-pixel enables "zero hertz" operation for static content.
* A quantitative comparison showing how backplane power can be reduced from ~200mW to just 1mW.
š **Clip Abstract** Discover the architectural secret to ultra-low-power microdisplays. Dr. Vogel explains how memory-in-pixel backplanes slash power consumption by over 99% compared to traditional frame-based designs, making all-day AR glasses a reality.
š Link in comments š
#MemoryInPixel, #MicrodisplayBackplanes, #ZeroHertzOperation, #LowPowerMicrodisplays, #WearableElectronics, #ARDisplays
This is a highlight of the presentation:
MicroLEDs, AR/VR Displays, Micro-Optics 2025: Innovations, Start-Ups, Market Trends
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00:04:10 - 00:05:45
Why might OLED be a better choice than MicroLED for your next wearable device?
Why might OLED be a better choice than MicroLED for your next wearable device?
This clip compares the fundamental operating characteristics of OLED and MicroLED emitters for microdisplay applications. While MicroLEDs operate at a slightly lower voltage (2-4V) compared to stacked OLEDs (up to 5V+), the key difference lies in their current density requirements for peak efficiency. This is a critical factor for power consumption in battery-operated devices like smart glasses.
The efficiency maximum for OLEDs occurs at a much lower current density, around 100 milliamps per square centimeter. In contrast, MicroLEDs reach their peak efficiency at significantly higher current densities, in the range of 1 to 10 amps per square centimeter. This difference of several orders of magnitude has profound implications for system design and power budgeting.
This fundamental difference in operating current density provides a strong indication that for applications where the absolute lowest power consumption is the primary goal, such as in "look-around" smart glasses with long battery life requirements, OLED technology currently holds an advantage over MicroLED. However, for applications demanding very high luminance, MicroLED remains the preferred choice.
In this short video, you can learn:
* The typical operating voltages for OLED and MicroLED microdisplays.
* The concept of "efficiency maximum" and how it differs dramatically between the two technologies.
* Why OLEDs are better suited for ultra-low-power applications, while MicroLEDs excel at high brightness.
š **Clip Abstract** Dr. Uwe Vogel presents a nuanced comparison between OLED and MicroLED efficiency, challenging the common assumption that MicroLED is always superior. He explains that OLEDs reach peak efficiency at far lower current densities, making them the better choice for ultra-low-power wearable devices.
š Link in comments š
#OLEDMicrodisplays, #MicroLEDMicrodisplays, #DisplayEfficiency, #CurrentDensity, #ARDisplays, #WearableDisplays
00:09:56 - 00:11:55
Are inefficient waveguides killing your AR display's brightness and battery?
Are inefficient waveguides killing your AR display's brightness and battery?
A major challenge in AR systems is the low optical efficiency of waveguides, which are commonly used as combiners. These components can waste over 99% of the light generated by the microdisplay, forcing the light engine to be incredibly bright and power-hungry. This is an unsustainable approach for battery-powered wearables, which are typically limited to a total capacity of less than one watt-hour.
Fraunhofer IPMS proposes a radical solution: eliminate the separate waveguide entirely by making the microdisplay itself semi-transparent. This is achieved by fabricating the OLED-on-CMOS display on a Silicon-on-Insulator (SOI) wafer. After the OLED frontplane is deposited, the underlying silicon "handle" wafer is removed, leaving the active circuitry on a thin, transparent layer.
This innovative device architecture features clusters of active, light-emitting pixels with transparent areas in between, allowing the user to see the real world directly through the display. The display itself becomes the combiner, creating a virtual image with the help of simple micro-optics. This approach promises a dramatic improvement in overall system power efficiency by avoiding the massive light loss associated with traditional waveguides.
In this short video, you can learn:
* Why the low efficiency of waveguides is a critical bottleneck for AR systems.
* How a Silicon-on-Insulator (SOI) process enables the creation of a semi-transparent backplane.
* The concept of using a transparent microdisplay with pixel clusters as an integrated combiner optic.
š **Clip Abstract** Dr. Uwe Vogel introduces a novel approach to AR optics that replaces inefficient waveguides with a semi-transparent microdisplay. By using an innovative SOI fabrication process, the display itself acts as the combiner, promising huge gains in system-level power efficiency.
š Link in comments š
#TransparentMicrodisplay, #SOIProcess, #OLEDOnCMOS, #IntegratedCombiner, #ARDisplays, #WearableElectronics