Human-Machine Interface for Gesture Sensing




Camera for gesture sensing is not able to work effectively at close range and the setup drains the battery of the electronic device quickly. Current pyroelectric sensors are slow and lack the sensitivity to accurately sense different types of motion. A transparent and stretchable film has been developed to overcome the problems described above. The sensor based on the film is able to detect motion or gesture effectively at close range. The film, which can comprise graphene and pyroelectric materials, is more power-efficient than the setup based on cameras as it depends on the infrared heat it senses to generate the necessary signal. The transparency of the film allows it to be “pasted” over any electronic display screen, making the screen capable of gesture-based interaction with a user. The sensor based on this technology is fast, sensitive and highly responsive compared to the conventional pyroelectric IR sensors.


The sensor based on this technology can comprise a transparent pyroelectric layer sandwiched between a top electrode and a rear electrode. The top and rear electrodes can be made of graphene while the pyroelectric layer can be made of polyvinylidene fluoride (PVDF) and its copolymers such as polyvinylidene fluoride-cotrifluoroethylene (PVDF-TrFE). If optical transparency is not required, the pyroelectric layer can be made of lead zirconate titanate (PZT). The pyroelectric layer undergoes a reorientation of dipoles when there is a infrared radiation received through the graphene top electrode. Besides graphene, the rear electrode can alternatively be made of indium tin oxide or silver nanowire. If optical transparency is not required, the rear electrode can be made of gold, nickel or copper. The top and rear electrodes can be designed and arranged in such a manner for an infrared radiation to be detected and its location determined as a pair of X and Y-positions. The advantages of the sensor of this technology include: (1) Lower power consumption because the sensor depends mainly on heat radiation from the user to generate signal based on pyroelectric effect, (2) No accidental touch problem because the pyroelectric effect requiers a change in temperature to generate a signal, thus continuous contact with the warm body of the user does not result in continous generation of signal, and (3) Ability to be deployed over a large screen such as that of a information panel and tablet.


The sensor of this technology can be deployed in many electronic devices where interaction with the device through hand gesture is desirable. For example, when deployed in the screen of information panel commonly deployed in public places such as shopping malls, the ability to interact with the screen through gestures enables the users to obtain information without having to touch or swipe the public screen. For personal device such as tablet, the ability to interact with the screen through gestures becomes very useful in humid environment when touching will leave behind significant amount of finger prints or when swiping becomes uncomfortable due to increased surface resistance.


In the pandemic situation today, using gesture to interact with an electronic screen in public instead of touching and swiping the screen helps to reduce transmision of virus from one person to another. In humid environment when touching and swiping a screen is uncomfortable, ability to interact with the screen through gesture makes the use of the device enjoyable.