ShiftLens: 3D-printed surfaces that change their image without electronics

A team at MIT has presented ShiftLens, a system for 3D-printing objects whose surface changes its appearance when you press, slide, or turn them, with no sensors, batteries, or screens involved. It was developed in the Human-Computer Interaction Engineering Group at CSAIL. What interested me most was the idea that an object can show its own state.

The example is a reagent bottle: when the cap is screwed on tight, a checkmark appears, and when the cap is loosened, a hazard symbol shows up. Both images are printed directly into the bottle wall. A door sign also switches between two displays with the flip of a lever.

Technically, ShiftLens combines a layer of lenticular lenses, like the ones on flip-image postcards, with a pattern layer underneath where the images are split into narrow, interleaved stripes. When the lens layer shifts by a few millimeters, the lenses magnify different stripes, and a different picture becomes visible. The movement comes either from the user's own action, such as unscrewing a cap, or from a built-in mechanism like a switch or a wheel.

Lenses, colors, the base body, and the mechanics are all produced in a single print. The team used a Stratasys J55 with material jetting, where water-soluble support material fills the gaps and is washed away afterward. The limits are real, though: structures thinner than 200 µm cannot be printed, at a 5 mm lens pitch there are at most ten states, and the geometry is restricted to translation and rotation surfaces.

Source: 3Dnatives