Kedar Sathaye | Konica Minolta: Which optical losses must be mapped backwards from the eye, not just corrected on the panel?
15:15 - 17:11
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Summary of the clip:
Which optical losses must be mapped backwards from the eye, not just corrected on the panel?
The final image is the product of the complete optical chain. That chain includes the source and illumination, polarization loss, field, the MTF of the projection system, the waveguide with coupler loss and color variation, and finally pupil position. Demura must therefore capture panel plus optics plus waveguide plus assembly effects at that eye position, not the panel alone.
The method is sequential and feedback-based: measure the final image, map it backwards toward the panel, then correct the panel again. Reintroducing non-uniformities in the panel is possible because the optical setup itself introduces non-uniformities. First define the measurement conditions; the instruments are calibrated for flat field color distortions, gray light, et cetera. Then register image geometry and capture patterns: RGB, white, black, and multiple gray levels, before solving the correction.
What results is a correction map derived from the eye position and propagated back through the optical chain. The correction methods remain similar to panel-level Demura: the space pixel method or the fractional pixel method. Because waveguide coupler loss, color variation, polarization loss, MTF, and pupil position all contribute, the final map must represent panel, optics, waveguide, and assembly effects together rather than as separate layers.
In this short video, you can learn:
* Final Demura must capture panel plus optics plus waveguide plus assembly effects at the eye position.
* The correction is sequential and feedback-based: measure the final image, map backwards to the panel, then correct the panel again.
* Solve correction using the space pixel method or fractional pixel method after capturing RGB, white, black, and multiple gray levels.
đź“‹ **Clip Abstract** The final image is the product of the complete optical chain, so image quality loss arises from source, illumination, polarization loss, field, MTF, waveguide coupler loss, color variation, and pupil position. Demura must therefore capture panel plus optics plus waveguide plus assembly effects at the eye position, using a sequential feedback correction map that measures the final image, maps backwards to the panel, and corrects the panel again.
About the speaker:
* Speaker: Kedar Sathaye
* Company: Konica Minolta
* Event: Eindhoven 2026
* Location: High Tech Campus, Eindhoven
#Demura, #WaveguideCouplerLoss, #SpacePixelMethod, #FractionalPixelMethod, #ARVRDisplays, #NearEyeOptics
This is a highlight of the presentation:
Virtual Demura for AR/VR Displays: A Near-Eye Case Study
More Highlights from the same talk.
03:01 - 04:41
If microLED pixels range from 2 to 10 million candelas per m², what does that do to the final image?
If microLED pixels range from 2 to 10 million candelas per m², what does that do to the final image?
Because every pixel is itself a light source, each microLED must be considered individually. The talk points to spatial variability in luminance and spatial variability in color across those pixels. Together these variations produce a display that is not completely uniform. That final non-uniformity is called mura, or unwanted brightness dependency, spread across the display. The non-uniformity can be seen on the individual pixel level.
Color variation is illustrated with an exaggerated range between 510 and 590, used only for simplicity to show that pixels in various locations can differ in color. Luminance variation is equally explicit: microLED displays are known to reach millions of candelas per meter squared. If one pixel outputs 2 million candelas and another outputs 10 million candelas, the display already contains a large luminance variation. This is the core spatial variability challenge described for microLED sources.
The challenge grows from small pixel size and high pixel density, because each source must be individually accounted for. Spatial luminance variability and spatial color variability combine into a non-uniform display. The result is a mura condition with unwanted brightness dependency across the display. At the individual pixel level, that non-uniformity is visible. The example of 2 million versus 10 million candelas per meter squared shows how quickly a large luminance range appears, making uniformity a defining problem for microLED displays.
In this short video, you can learn:
* Every pixel is itself a light source, so variation across pixels must be taken into account individually.
* Spatial luminance variability and spatial color variability together create a display that is not completely uniform, called mura or unwanted brightness dependency.
* MicroLED displays can reach millions of candelas per meter squared, and a 2 million versus 10 million candela example already shows a large luminance variation.
đź“‹ **Clip Abstract** MicroLED displays face non-uniformity because each pixel is an individual light source. Spatial luminance and color variations produce mura, or unwanted brightness dependency, with a 2 million versus 10 million candela per meter squared example showing large luminance variation.
About the speaker:
* Speaker: Kedar Sathaye
* Company: Konica Minolta
* Event: Eindhoven 2026
* Location: High Tech Campus, Eindhoven
#MicroLEDMura, #PixelLuminanceVariation, #SpatialColorVariability, #CandelaPerMeterSquared, #NearEyeDisplays, #ARVRDisplays
20:23 - 21:18
Can demura of a million-pixel microdisplay run fast enough for a production line?
Can demura of a million-pixel microdisplay run fast enough for a production line?
When evaluating display characterization workflows, the time required to test a high-resolution microdisplay is a critical concern for production lines. For a microdisplay containing up to one million pixels, the exact duration of the testing process depends on several operational parameters. However, even with these variables, the total measurement time does not stretch into hours due to the capabilities of modern imaging hardware.
The combination of high-performance cameras and advanced analysis software enables rapid data acquisition. For a very bright or high-resolution display, a single measurement can be completed in just a few milliseconds. This rapid cycle time ensures that the initial optical capture does not become a bottleneck during the characterization process, even when dealing with dense pixel arrays.
Even when the testing protocol demands multiple iterations to ensure accuracy, the throughput remains highly viable. If a comprehensive evaluation requires up to fifty separate measurement iterations, the entire sequence is expected to take no more than a couple of minutes. This speed makes high-resolution pixel characterization highly practical for demanding display manufacturing environments.
In this short video, you can learn:
* A single measurement of a high-resolution or very bright microdisplay can be completed in just a few milliseconds.
* The total testing time for a million-pixel microdisplay depends on specific parameters but is measured in minutes rather than hours.
* Even a complex testing cycle requiring fifty iterations of measurements takes no more than a couple of minutes to complete.
đź“‹ **Clip Abstract** This case study addresses the testing time required to characterize high-resolution microdisplays up to one million pixels. By leveraging fast cameras and software, single measurements take only milliseconds, keeping even fifty-iteration test cycles under a few minutes.
About the speaker:
* Speaker: Kedar Sathaye
* Company: Konica Minolta
* Event: Eindhoven 2026
* Location: High Tech Campus, Eindhoven
#MicroDisplay, #PixelMeasurement, #DemuraTesting, #OpticalMetrology, #DisplayMetrology, #NearEyeDisplays
08:07 - 09:51
Why does demura need a feedback loop of sequential dot-matrix patterns instead of one camera measurement?
Why does demura need a feedback loop of sequential dot-matrix patterns instead of one camera measurement?
A high-resolution image-based measurement system is paired with an optic that can be a microscopic optic offering up to 20x magnification. The sensor cited is a 61 megapixel CCD, and a 151 megapixel camera is now available to measure even high-density or high-resolution displays. After registering regions of interest, the system measures average signal—luminance in this case—and computes a correction factor that is then applied.
It is an iteration of process, not a one-measurement correction. A measurement is taken, and the process is essentially a feedback loop until the result is right. Two methods exist; the spaced pixel test patterns method uses a series of dot-matrix test patterns. The display is not illuminated all at once but in a very sequential manner, from pattern one to pattern—however many are needed—before measurements are recorded and corrected using lookup tables.
Within that sequential illumination, pixel luminance and color uniformity are recorded, along with everything else the measurement captures. The correction factor derived from the average signal in each region of interest is applied iteratively. The camera resolution—61 megapixel now, 151 megapixel available—sets how finely this can be done for high-density displays. The loop continues until the right correction is reached; a single camera measurement is not enough because the correction is computed and then verified rather than assumed.
In this short video, you can learn:
* A 61 megapixel CCD is cited, with a 151 megapixel camera now available for measuring even high-density or high-resolution displays.
* Measurement uses a high-resolution image-based system with an optic up to 20x magnification, regions of interest, and average luminance to compute a correction factor.
* Demura is not a single measurement: it is a feedback loop, and the spaced pixel test pattern method sequentially illuminates dot-matrix patterns before correcting with lookup tables.
đź“‹ **Clip Abstract** High-resolution image-based measurement, using a 61 megapixel CCD or a now-available 151 megapixel camera and optics up to 20x magnification, captures average luminance in registered regions of interest to compute a correction factor. Because a single measurement is insufficient, the process runs as a feedback loop, and the spaced pixel test pattern method sequentially illuminates dot-matrix patterns before pixel luminance and color uniformity are corrected using lookup tables.
About the speaker:
* Speaker: Kedar Sathaye
* Company: Konica Minolta
* Event: Eindhoven 2026
* Location: High Tech Campus, Eindhoven
#151MegapixelCamera, #SequentialDotMatrixIllumination, #LookupTableCorrection, #DemuraFeedbackLoop, #DisplayMetrology, #NearEyeDisplays