Researchers at the University of California, Santa Barbara have created a novel display technology that produces images people can both see and feel. The research, led by Max Linnander in Yon Visell’s RE Touch Lab, addresses a long-standing question about whether light that forms an image can also be converted into a tactile sensation. The project began after Visell posed a challenge when Linnander arrived in late September 2021; after nearly a year of tests and simulations the team built laboratory prototypes. In December 2022 Linnander demonstrated a simple working prototype: a single pixel excited by brief flashes from a small diode laser.
The displays use arrays of millimetre-sized optotactile pixels on thin surfaces. Each pixel is optically addressed by a low-power scanning laser that both illuminates and powers it. Inside a pixel a suspended thin graphite film absorbs the light and quickly heats the trapped air in a small cavity. The rapid air expansion deflects the pixel’s top surface outward by as much as one millimetre, producing a perceptible bump above the illuminated pixel. By scanning the beam across many pixels in sequence, the system generates dynamic graphics — contours, moving shapes and characters — with a refresh rate fast enough for continuous animation.
Because light supplies both illumination and power, the surfaces need no embedded wiring or electronics; a small scanning laser sweeps the surface at high speed. The team has demonstrated devices with more than 1,500 independently addressable pixels. User tests indicate people could localise individual illuminated pixels with millimetre precision, perceive moving graphics accurately, and discriminate spatial and temporal patterns. Suggested applications include high-definition visual-haptic touchscreens for automobiles and mobile computing, electronic books with tangible illustrations, and architectural surfaces for mixed reality. Visell also notes historical antecedents: in the 19th century Alexander Graham Bell and others used focused sunlight and rotating blades to excite sound in air-filled tubes; the new work applies similar physical principles to modern digital displays. The research source is UC Santa Barbara.
- High-definition visual-haptic touchscreens
- Electronic books with tangible illustrations
- Architectural surfaces for mixed reality
Difficult words
- novel — new and different from what existed before
- tactile — relating to the sense of touch
- pixel — small light element in a display imagepixels, pixel’s
- diode — a small electronic device that makes light
- suspended — held freely in place without support below
- cavity — a small hollow space inside something
- deflects — to change direction of something slightly
- illuminates — to shine light on or make visibleilluminated
- localise — to find the exact place of something
- discriminate — to notice or tell differences between things
Tip: hover, focus or tap highlighted words in the article to see quick definitions while you read or listen.
Discussion questions
- Which of the suggested applications in the article (touchscreens, electronic books, architectural surfaces) do you think would be most useful? Why?
- What challenges might engineers face when making these displays for cars or mobile devices?
- How could displays that you can both see and feel change reading or learning with electronic books?
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