I have spent a good deal of time thinking about how Apple (AAPL 1.66%) can further enhance the follow-on to this year's rumored iPhone 8 with OLED display.

Indeed, with Apple moving to (potentially curved) OLED displays, finding additional innovations that will dramatically improve the user experience in future generations is going to be tough.

That said, there are several ways that I can see Apple improving the display technology of the premium iPhone that's likely coming in the fall of 2018. Let's go over them.

Apple's iPhone 7 in Jet Black with a pair of AirPod wireless earbuds.

Image source: Apple.

Higher refresh rate display

One of the rumored new technologies coming to this year's 10.5-inch iPad Pro -- whenever it happens to launch -- is a high-refresh rate display.

What a high-refresh rate display does is basically make everything look and feel smoother. It's one of those features that's hard to describe, but once you see it, it can be a real game changer.

I don't think a high-refresh rate OLED display is in the cards for this year's iPhone 8 -- manufacturing high-quality OLED displays that support the standard 60Hz refresh rate in high volumes is already going to be tough -- but it sounds like something that could come to the successor to the iPhone 8.

Larger screen size options

In a prior article, I suggested that Apple is leaving some potential revenue/profit on the table by only offering this year's premium iPhone in a single screen size.

I could see Apple offering two different screen sizes for its premium iPhone line next time. Not only would doing so allow Apple to successfully serve a wider range of customers (one report claimed that Samsung's (NASDAQOTH: SSNLF) Galaxy S8/S8+ production split recently went from 60/40 to 55/45, so clearly there's demand for even larger screens), but it would be a straightforward way for the company to enrich its product mix (boosting revenue and profits). 

How about a curvier display?

There have been mixed messages about the potential curvature of the iPhone 8 display. Some rumors say the display will curve into both edges, like what the displays on Samsung's Galaxy S8 and S8+ do.

Other reports say that the display's curve will be much gentler, more akin to the curvature of the cover glass found on the iPhone 6 and later models.

I'm inclined to believe that this year's iPhone 8 will have a relatively gentle curve, with potentially more aggressive curvature coming in future models.

It's possible that holding back on the curvature will make it easier to manufacture screens to Apple's specifications this time around (and if reports are true, Apple wants a lot of them), allowing Apple and its supplier(s) to work on bringing manufacturing yields of curvier displays up for the late 2018 premium iPhone models.

More advanced 3D Touch

With the iPhone 6s, Apple introduced a feature known as 3D Touch. This feature, as Apple describes it, "senses how deeply users press the display."

The implementation in the iPhone 6s and iPhone 7 smartphones is quite good, but I find it difficult to believe that Apple is "done" with 3D Touch. I'm sure the company's marketing and engineering teams are exploring potential extensions/addition to the technology.

I don't think we'll see a "3D Touch 2.0" in this year's iPhone -- Apple probably has its hands full just trying to get 3D Touch to work with the new OLED display technology -- but a more advanced form of 3D Touch might be in the cards for the 2018 iPhone lineup and beyond.