BARCELONA — OnePlus CEO Pete Lau, who is very picky about corners, doesn't like the ones he sees on the folding phones here at MWC19.

"It's not product excellence, having to stop at that level of large curvature," he said through a translator. "My focus is on the flexible OLED technology, and as that advances and gets really good, what possibilities there are. When those fields can get really small and tight, what possibilities are there for the screen technology?"

Of course Lau would be talking about the degrees of fold. The cult phone-maker CEO, who has an engineering background, is informally known as the chief product designer at OnePlus, and once showed me how he obsessed over the corner radius when developing the OnePlus 6.

While other companies have been launching 5G phones here at MWC19, OnePlus is sticking with a teaser. Up in the Qualcomm booth, the company has what looks like a very long screen covered by a plastic shroud. The apparently tall, narrow screen is a bit of an optical illusion, caused by the casing, Lau said; what's under there is more likely to be a more normal-looking smartphone.

"It has to go back to a form factor that's desirable by the wider community … [I] don't see that as a radical shift from the form factor of what already exists," Lau said.

While OnePlus hasn't decided on the name for the 5G phone yet, it sounds like it won't be called the OnePlus 7. At least for now, OnePlus will be running two parallel product lines: a broadly available 4G phone line and specialized 5G products for specific carrier partners.

"The 5G products have to be customized for the individual carrier in the individual country, where the 4G product works on every network," Lau said.

Instead of focusing on radical form factors, OnePlus is trying to develop a 5G app ecosystem. At a panel yesterday, Lau announced a competition for OnePlus fans to develop 5G app ideas. Game streaming from the cloud will definitely be one 5G application, and that led to a theme Lau thinks groundbreaking 5G apps will have.

"I think for the first stage, what a lot of feedback will be about is the tightening of the closeness between the device and the cloud. The speed between the two, what possibilities are there on that front?" Lau mused.

Leaning on the cloud more will probably require new service plans, and Lau warned that might take a little while. "Looking at the 3G to 4G transition, that was also very expensive at the beginning," he said.

"But a technology transition as significant as this is, is going to bring about a change in carrier business models. Their focus on payment for certain amounts of data will transition; what it will turn into, I don't know," he said.