Responsive Dynamic Three-Dimensional Tactile Display Using Hydrogel Concept: A responsive flexible 3D interface assisting visional impaired people to communicate.

Responsive Dynamic Three-Dimensional Tactile Display

Using Hydrogel Concept: A responsive flexible 3D interface assisting visional impaired people to communicate with modern IT (Information Technology) world and health care service. With this tool they can more effectively understand image-assisted content and interact with electronics devices, that will open them a door to reach much wider world.

Functions: The surface of interface provides real-time 3D topological shape change according to input information, such as image brightness, color map and so on. For example, a 3D display may have 256 X 256 pixels, with 32 level of height variation for each pixel. The higher brightness of optical image pixel, the higher height of tactile display pixel. Blind people will FEEL the image brightness distribution by the sense of tactile height distribution.

Technology and Team: The system is fabrication with hydrogel material with scalable micro manufacture technology. The collaboration between visional impaired people, Material Engineering, Mechanical Engineering, Bioengineering, Electrical engineering, and education experts are essential for the success of system development.

System Concept View

A responsive tactile display skin is a flexible interface to produce a dynamic 3D tactile surface representing the optical light intensity distribution from an underlying iPhone, iPad, or computer screen.

A stand-alone responsive tactile display is to produce a dynamic 3D tactile surface representing the optical light intensity distribution from electric input files.

System Schematics with Building Modules

3D tactile topology shape changing unit based on hydrogel

Stand-alone unit

data input, converting and process unit

Active Smart skin unit

3D tactile topology shape changing unit based on hydrogel

data converting and process unit

Light information acquisition unit to extract the information from attached optical display

Self responsive smart skin unit

3D tactile topology shape changing unit based on light sensitive hydrogel. When attaching it to optical display, the light from optical display will work as stimulus to drive the topology change of hydrogel

Building Material - Hydrogel

Hydrogel = solvent (usually water) + (a network of polymers): Responsive to Environmental Stimuli.

collapsed swollen

Stimuli, which cause the hydrogel shrinking or swelling• temperature• pH• ions

reversible

• enzymes• electric field• light

Example: Thermal Responsive Hydrogel

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Galaxy optical image

Hydrogel swelling: transition temperature, slope, and dimension change can be tuned through chemical composition/solvent.

Modeling of 3D tactile display based on temperature sensitive hydrogel (based on right hand swelling ratios)

Pixel Design Based on Hydrogels

Package to enclose the hydrogel and solventSolvent

Stimulation component for each pixel

Hydrogel block for each pixel

Display pixel

Different types of stimuli can be employed, such as heat, cooling, light, electrical field, pH and so on, depending on the type of hydrogel used. Pixel separator is designed to isolate individual pixel to avoid crosstalk and improve stimulation efficiency.

For example, when we use heat to drive a temperature sensitive hydrogel, a well constructed thermal insulation cavities may stand between pixels. Or when we use light to drive photosensitive hydrogel, a light blocker is needed between two pixels.

Pixel separator

solvent

Hydrogel

Stimulation component

Technology Development - Hydrogel Design,Synthesis, and Optimization

Two General Approaches:• Thermoresponsive hydrogels (Upper critical solution temperature (UCST) ones

are preferred, for example, poly(acrylamide)/poly(acrylic acid) interpenetrating network. )

• Light sensitive hydrogels, for example, chlorophyllin based hydrogels which are sensitive to visible light.

The transition temperature, dimension change, and response rate will be optimized by co-monomer, solvent, and additives.

Preliminary work on Poly (N-isopropylacrylamide) (PNIPAAm)

(More on next slide)

Technology Development - Mechanics of Integration of Soft and Hard Materials

Interactions between multiphysics fields --- two focused investigations:

(1) Material model to understand how hydrogel behaves under various stimuli

(2) Numerical platform for concurrent deformation of soft gels and hard packaging materials

Si elements

PDMS (adhesive)

PNIPAAm (temperature sensitive gel)

Heat up: shrink

Cool down: swell

T =0 @ RT T = 2 min @ 45oC Tunable curvilinear gels integrated with hard materials

350X

Technology Development Detail --- 3, Pixel Component Development

PhotodiodeOptical intensity acquisition from attached optical display with be performed with (1) photodiode built on flexible substrate for active smart tactile skin, and (2) a optical lens array on flexible substrate.

solvent

Solvent encapsulation and pixel separation will be realized with micro- manufacturable polymer – Parylene-C and air cavitiesSince involving solvent (e.g. water), fabrication should be at low temperature and wafer compatible. This will bring great challenge of microfabrication and packaging. Various processes will be explored.

Top dynamic surface will be covered by an elastomer polymer, for example, polydimethylsiloxane (PDMS), which will conformally change the shape with swelling of hydrogel. PDMS will protect hydrogel from contacting environment and hand touching.

The responsive 3D dynamic tactile display may become smart by integrating a sensor module and central intelligent electric unit. Then it becomes fully functional two-way tactile interface.

3D tactile display Module

Tactile Sensor Module

Data analysis and process Module

Responsive Smart

Other potential applications:Gaming control interface;Emergency human machine interface in addition to optical and sound interface, while space crew or plan pilot loose their sight.

Gain on Fundamental Research and Education

Education• A evolutional interface to assist the education of visional impaired people.• Understanding of methodology of employing this new interface for education.

Applications• A new dimension for human-machine interface.• Potentially wide consumer electronics applications.

Science and Engineering• Design, synthesis, and optimization of responsive hydrogels• Understanding the mechanics of integrating soft and hard materials.• Development of a scalable micro-manufacture technology using combination of

soft and hard material, polymer and solvent.

Research Team

Responsive 3D tactile displayVisional Impaired people and other customers

Device Development

Chem

ical E

ngineering: D

r. Lenore D

ai

Mechanical

Eng

ineering: D

r. H

anqing Jiang

Electrical E

ngineering:

Dr. H

ongyu Y

u

Com

pute

r Enginee

ring: D

r. Baoxin Li

Education Development

Biologist:

Dr. D

ebra B

aluch

Scientific Lead: Dr. Rogier Windhorst

Astronom

er: D

r. Rog

ier Win

dhorst

Edu

cation E

xpert:

Dr. Terri H

edgpeth (blin

d)

Blin

d Stud

ents: A

shleigh G

onzales, …