A diffusion filter to eradicate the remaining SDE, without blurring the image?


Hi, @PimaxVR, a suggestion: could you add a diffuser to the screen, similar to the new LG system to reduce the SDE? If we remove 70% of the SDE, we would surely eradicate the SDE once and for all.

With this system, the picture only starts to get blurry when you remove more than 70% of the opaque separation between pixels.


Maybe on the vive or rift, but it would do more harm than good here.


Why? There are any downsides?


It increases blurriness


Side effect of diffusers is less sharp picture. I’m interested how that LG patent will work in practice, but it would be almost a miracle if it was without a downside.


Not in this system, it seems: it starts to get blurry when you exceed 70% of SDE reduction.
If we just reduce 50% of the SDE, the picture will be clearer, and without SDE (I hope)


The entire basis of a diffusion filter is that it decreases sharpness. Will you be able to tell it? Maybe not, but not worth the risk in my opinion. I’ll come back later when freshpatents is up again so I can read through it.


Considering that only SOME of the reviewers say they can see SDE - and only if they look hard for it - and other people have said they don’t see any SDE at all even when looking for it…I’d say the SDE problem has been solved by Pimax, no need to waste any time trying to fix something they’ve already fixed.


Surely many did not notice it because they were amazed by the FOV; the most specialized people who went to look for it, found it. I think that being so close to getting a completely clean image, it’s a pity not to try to eliminate it completely.


Like I said, there was more than one reviewer who said they looked for SDE and saw none. It’s a non-issue.


The whole point of the 8k is to get rid of SDE; you don’t get any extra detail at all with the Pimax 8k over the 5k, what you get is lack of SDE. We don’t need extra filters blurring the image, we already have the high resolution screen.

I would bet the couple people who said they saw SDE mistook it for seeing aliasing or seeing the pixels. Seeing pixels is not the same thing as seeing the spaces between pixels. I see pixels at the theater these days, if I look for them, but I don’t see a screendoor effect.


the Razor HDK 2 headset is using some kind of diffusion filter, few report that people prefer the unit without the diffusion filter.


Well, if it “diffuses light emitted from a light-transmitting area of a display panel to a light-blocking area of the display panel” and “improves the image quality of the display.” as stated in the article, I would assume it is an additional layer in between panel’s backlight plane and the switching plane.

If correct, then “adding it to the Pimax” would mean basically to design new displays.


A diffusion filter is blurring. It is what it does. You cannot ask for a diffusion filter that does not blur the image therefore.
That being said the high screen resolution is doing just that - reducing the SDE. That is why the 8k is better than the 5k - they both run on the same resolution.


You are right. Increasing the display resolution while keeping the same low input res (and have it upscaled) is another way to address the SDE. The only downside is that the higher res panel needs higher bandwidth to process the same information, and may not be up to the task.

What we saw right now with Pimax 8K and its 4K panels, which have apparently troubles handling 90Hz refresh, while the lower res panels from Pimax 5K could possibly handle it better.


There is no bandwith issue here. The upscaling is done on the headset by the scaler-chip.
The Pimax 5k and the Pimax 8K get exactly the same signal and use exactly the same bandwith. The only difference is the upscaling on the 8K. If available (display and upscaler) you could use 16k displays instead too.

Only on the Pimax 8K X you’re looking at a bandwith issue since the full resolution has to be sent to the HMD via Displaypoert. That is why they’ll need two cables. Good luck on getting the Pimax 8K X wireless btw. Backers of the 8K X who think they’ll get a wireless module better be prepared for disappointment.


Actually, when I wrote bandwidth I meant the data flow/rate on display/panel interface on the hardware level, not on the display port. I used bandwidth for simple lack of better word, could have used data rate.

The point is, running 4K display (38402160) at 90 Hz requires 812 MHz pixel clock. Running 25601440 (Pimax 5K display and Pimax 8K resolution) at 90 Hz requires 368 MHz pixel clock. So the data rate required by 4K display is more than twice compared to non-upscaling solution.

The panels Pimax is using for 8K seems to be not rated at these operating speeds, so they face problems. Using lower res panel with significantly lower data rate may actually give better chances to make it operational at 90 Hz.


I see and I agree. I am pretty sure the 5k version has no issues achieving 90hz eventhough Pimax has not said anything about it so far.