RFC: Touch-panel Construction

Technology Reserve is seeking Technology Packages, deposits and expertise in touch-panel display controls. 


Touch-panel controls are becoming ubiquitous as a replacement for manual controls. Typically, touch-panel “buttons” are lit by edge-emitting LEDs that pass light into a guiding layer constructed to release light only in defined regions. When properly prepared, these light-guiding layers deliver smooth, even illumination across the button.

A light-guiding layer traps light similarly to an optical fiber. The guiding layer has a high-refractive index and is bordered by a layer of low-refractive index. To provide the best possible optical performance in a conventional construction, this low-refractive-index layer is an air gap. However, air gaps have one significant drawback—there is no mechanical integrity to support subsequent over layers. As a result, this light-guiding technology cannot be incorporated into a thin-film structure because the films suspended over the gap are inherently weak, and the air gap will collapse if the laminate is heated, pressed, or bent.

Technology Reserve’s client is seeking a new solution to emit light from buttons on a thin, flexible, touch panel. An example solution may be a light-guiding laminate that is both optically efficient and mechani- cally robust. This may be accomplished either through an innovative mechanical construction capable of supporting an air cavity, or by applying new materials combinations that deliver uniform, bright illumination out from the button regions. Alternative solutions to delivering light may incorporate surface emitting LEDs, such as organic LEDs, as long as the resulting laminate is flexible and produced at a sufficiently low cost to enable high-volume manufacturing.

Key Capabilities:

  • Flexible laminate materials expertise, especially in a high-volume industry such as flexible PCBs
  • Optical expertise including understanding of light guiding principles

An ideal expert partner will:

  • Demonstrate a functioning prototype incorporating evenly lit touch controls
  • Work with the client’s engineering representatives to transfer or co-develop the necessary IP and produce a solution integrated with client’s existing capabilities

 For inquiries, contact Astha Vijay, astha@techreserve.com