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. collapsedswollen Stimuli, which cause the hydrogel shrinking or swelling temperature pH ions reversible enzymes electric field light

Example: Thermal Responsive Hydrogel 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 solvent Solvent 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 RT T = 2 45 o C Tunable curvilinear gels integrated with hard materials 350X

Technology Development Detail --- 3, Pixel Component Development Photodiode Optical 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 cavities Since 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 display Visional Impaired people and other customers Device Development Chemical Engineering:Dr. Lenore DaiMechanical Engineering:Dr. Hanqing JiangElectrical Engineering:Dr. Hongyu YuComputer Engineering:Dr. Baoxin Li Education Development Biologist:Dr. Debra Baluch Scientific Lead: Dr. Rogier Windhorst Astronomer:Dr. Rogier WindhorstEducation Expert:Dr. Terri Hedgpeth(blind)Blind Students:Ashleigh Gonzales, …