Transparent, flexible, thin sensor surfaces for passive light-point localization based on two functional polymers

We present light-point localization by transparent, flexible, thin sensor surfaces based on only two functional polymers: a thin film of pyroelectric poly(vinylidene fluoride) (PVDF) combined with large-area polymer electrodes made of poly(3,4-ethylene dioxythiophene):poly(styrene sulfonic acid) (PEDOT:PSS). One of the electrodes is resistive to enable position sensitivity, and both materials are highly flexible and transparent across the visible range of light. We fabricated a one-dimensional sensor strip of 3.5 cm × 0.8 cm size and a two-dimensional 3 cm × 3 cm sensor surface. Both devices used a 25 μm thin PVDF film whose surface was activated by low-energy argon plasma. PEDOT:PSS electrodes were deposited by spin coating onto the PVDF film. The fabricated devices were validated by applying the intensity-modulated light of a red laser diode to the sensor surfaces. Our design enables position sensitivity without the need for active or passive matrix technology or external power supply, and with electronic circuitry placed only at the edges. This allows simple fabrication techniques to be employed, such as roll-to-roll-processing, spin coating and screen printing. Since low-cost polymeric materials can be used, the proposed sensors have a wealth of possible applications in consumer goods.