iFixit Shares iPad Mini 7 Teardown, Adds Mystery to 'Jelly Scrolling' Fix

Is there a technical reason why the iPad mini 5 either has no jelly scroll, or it wasn't a big enough issue like the mini 6? And if the mini 5 didn't have this, what caused the regression moving forward with the mini 6 and 7?

The pixels within an LCD panel (i.e. the actual “liquid crystals”) are not refreshed all at once for each new picture frame, but instead are refreshed line by line. This means that if you take a snapshot of the panel while it refreshes from one frame to the next, some of the pixels will show the new frame while others will still show the previous frame.

In addition, each pixel doesn’t change its state instantaneously, but needs a number of milliseconds to transition from the previous state to the new state. This means that in the snapshot, pixels will be in various degrees of blending between the old state and the new state. When comparing the first line with the last line, the first line may already have fully transitioned to the new frame, whereas the last line is still completely on the old frame. And the lines in between will be in some intermediate state.

Now, when you scroll perpendicular to those refresh lines, this means that one edge of the screen will already show the next scroll position while the other edge still shows the old scroll position. Due to the continuous state change of the pixels between those two edges, it looks as if the contents is slanted between the old and new scroll position.

This effect is stronger the narrower the display is in the problematic direction, and also the longer the pixel response time (the longer they take to change their state). If the response time is especially slow, it may even “smear” across multiple successive frames or scroll positions.

From the mini 5 to the mini 6, Apple (a) changed the refresh direction from the long side to the short side, and in addition (b) made the aspect ratio of the screen much narrower than before (from 4:3 to less than 3:2), and (c) (this is just my suspicion from comparing both side by side) the new panels have a worse pixel response time.

From what has been reported about the mini 7, my guess is that the response time (c) has been improved, but obviously (a) and (b) hasn’t changed.

Since the frame contents is transferred line by line from RAM to the panel, the lines are physically driven along either the long side or the short side of the display panel, and that’s where the display controller sits along the edge of the panel. Presumably, because the bezel widths changed from the mini 5 to the mini 6, it was more convenient to place the display controller along the long edge than the short edge, however with the side effect of switching to the refresh direction where the slanting effect is more pronounced.

Apple would have to switch that positioning back to the short side in order to completely eliminate the issue in portrait orientation. Apparently they didn’t want to invest the engineering effort to change the internal component layout of the mini again.

@Joe Rossignol IMO there isn’t much of a mystery here.

Is there a technical reason why the iPad mini 5 either has no jelly scroll, or it wasn't a big enough issue like the mini 6? And if the mini 5 didn't have this, what caused the regression moving forward with the mini 6 and 7?

I cannot believe we are discussing such minutia. I use my iPad mini 6 in the hospital almost every day, for 10-12 hours a day (for almost 2 years). This is not even on my mind.
Perhaps people should use it for real work, rather than just pure entertainment devices?

I use it for real work and notice the jelly scrolling. What is real work? I work at a hospital too....

I have absolutely no trust in Apple when it comes to their displays.

They use PWM (pulse-width modulation) aka flickering in almost all of their products. They have zero credibility.

I'm sure their "fix" for this iPad mini 7 is not without some compromise. Hopefully not, but we'll see. I'm picking up one of these next week.

lol. Okay. Enjoy?

Saw it in Best Buy - it’s still a terrible screen because of the refresh rate. Maybe the jelly scrolling is better but that low refresh rate stutter is a show stopper.

I find it curious that so many people used the iPhone before Promotion was ever uttered by Apple and it wasn’t the unusable device so many here and elsewhere want to claim devices to be now.

The redesign of the mini with 6th gen caused it.

You answered a "what" question with a "when" answer.