The folding phone market is heating up, and while smartphone manufacturer TCL has shown off concepts for some of its potential foldables, the company has yet to announce a concrete product. That isn't changing, but TCL today unveiled two new form factors it's exploring: a phone with a pull-out display, and one with a tri-fold design.

The pull-out phone concept was already leaked last month, but TCL is sharing a few more details today. The company is calling it "the world’s very first rollable extendable smartphone concept," with a thickness of 9mm and an AMOLED screen that extends from 6.75 inches to 7.8 inches. "When not in use, a motor-driven sliding panel utilizes advanced mechanics to conceal the flexible display," TCL said.

TCL promises there are no visible creases or wrinkles in the screen, but we've heard that claim before from other folding phones, and all of them have at least a minor crease where the screen folds. We'll believe it when we see it... or don't see it?

The company is also cooking up a tri-fold smartphone. In its folded shape, the screen is 6.65 inches in a 20.8:9 aspect ratio, but expands to 10 inches when fully unfolded.

"This is the first large screen tablet to leverage dual hinges and folds to achieve this type of product design," TCL said, "ensuring smooth folding inward and outward with a minimal gap, and features a multidimensional shine with a 3D holographic finish."

TCL says these are merely concept phones, so while it's possible these may never see the light of day, I don't think the company would release renders and detailed information about devices it had no intention of turning into finished products. We'll probably see these phones at some point in the future — and likely at high prices.