Until fabrics of polymer light-emitting diodes can be pixel-addressed in a garment, we will explore alternative methods of generating images in wearable art. This proposal investigates the possibility of creating a fabric which will generate a localized color-mapped display of the bending and stretching of the fabric.
We have considered non-electronic solutions, such as tribolumenescent materials, but these effects generally manifest in the destruction of the material. Liquid crystals require containing a fluid inside of a sealed, transparent flexible fabric and are passively viewed, reacting to external lighting. Holograms are printed on reflective foil and do not stand up to stretching or repeated bending. It is possible that other optically-active polymer materials may be developed and availabe in the future, but we could find no such materials available at the time of this writing.
Therefore, this proposal focuses on developing a material which will emit a colored light in response to local bending or stretching of the fabric. We will accomplish this by designing a fiber containing periodically-spaced strain gages, analog-digital hybrid integrated circuits and three-color light-emitting diodes (LEDs).
Three-Color LEDs are constructed from four semiconductor chips -- one red, one green and two blue -- surface-mounted with soldered leads, a reflector and an optical dispersion lens. In order to convert an analog value measured from the fabric into a color display, we will employ an analog-to-digital converter and a Read-Only-Memory (ROM) digital look-up-table. This will de-multiplex the single analog channel into three separate signals, one to drive each LED.
We will investigate two different fabric designs. The first is a "linear" version, meant to be woven into a fabric in a rectilinear fashion. This design will be sensitive primarily to bending of the fabric and will not yield to much stretching. The second design we will investigate is a fiber meant to be assembled into a fabric via a knitting paradigm. In this design stretching of the fabric is accomplished primarily through torsion to the knitting stitch, itself.
Garment assembly will be greatly simplified if electrical power does not need to be distributed throught the entire garment from an external source. We have not shown the seaming mechanisms which will be required to assemble garments from the fabrics we show here.
We intend to propose the initial design of our fabric as an open-source project in a standard Computer-Aided Design and Manufacturing (CAD/CAM) framework. We will leverage Moore's Law to evolve our design to smaller, faster and more dense cababilities with the evolution of manufacturing technology.