柔性显示一体集成的热释电自供能悬浮触控传感阵列

随着智能移动终端的迅速发展，人们对人机交互体验有了更高的要求。但是，当前基于外置机械系统、摄像头、红外线或毫米波等技术的人机交互方案还存在着诸多不足，如便携性差、功耗偏高、识别误判等，并且识别器件与显示器件难以一体集成，需要占据额外的空间，不利于移动终端的轻薄化发展。本文报道了一种基于红外热释电材料偏氟乙烯共聚物制备的自供能、高透过率悬浮触控传感阵列，该传感阵列能够与显示器件一体化集成，具有较高的透光率 (≥90%) 和较小的厚度 (数十微米)，以及针对不同距离与运动速度的手势识别功能。基于该类红外热释电薄膜器件的阵列传感技术有望支撑未来电子产品轻薄化以及多功能显示模组集成发展。

With the rapid development of smart electronic devices, the portable terminals are expected to operate under higher convenience and effectiveness of the input and feedback. Thus, human-computer interaction technology, including the directions input by touch control, voice recognition, visual tracking, and floating touch, is proposed to realize contact and non-contact information input. By integrating the human-computer interaction technology with the display devices, the user experience of the portable terminals can be largely improved. However, as a branch of human-computer interaction technology, floating touch suffers from several issues that impede its development in recognition, energy-efficiency, and portability. For example, the camera is susceptible to the surrounding environment of the recognized object, impacting the recognition accuracy of the sensor; the sensing distance of the millimeter wave sensor is limited by the attenuation phenomenon during the transmission of millimeter wave in the air; the transmitting devices and receiving devices of infrared sensor require high power consumptions, leading to increased energy use of the total portable terminals; the components are difficult to integrate with the flexible screen due to the large space they occupied and additional mechanical system, hampering the design of thin structure of the sensor. In this work, a PVDF-TrFE based flexible pyroelectric sensor is proposed to realize floating touch with portable, self-powered, and accurate recognition functions. Large-area pyroelectric PVDF-TrFE thin film with high uniformity is polarized via our self-designed polarization equipment, which significantly improves the polarization efficiency under low voltage conditions. The maximum polarization area can reach 300 mm×330 mm. In the experiment, we firstly compare the pyroelectric performance and light transmittance of films of different thicknesses. The optimal thickness of the PVDF-TrFE thin film is screened out to be 20 μm according to various indicators. Then the influence of movement speed and the distance of the heat source on the intensity of the responsive pyroelectric signal are studied. The results show that our sensor can not only recognize different speeds and feedback signals of different intensities, but also recognize different distances of the heat source. The farthest recognition distance is up to 100 mm. More importantly, our sensor has a small volume and thickness of only tens of micrometers. Such small occupancy leaves more spaces for integrating with display devices. The sensor also can be operated without external power supply, reducing the power consumption of the total mobile terminal. At present, we integrate the pyroelectric sensor under the metal layer of the display device. Across the whole display module, our sensor can still detect the limb movement track above the screen and record it in the form of electrical signal. Due to high transmittance which is up to 90% of the PVDF-TrFE film, our sensor is expected to lift above the light-emitting layer when integrating with a display device. This can further increase the detection distance, the sensitivity, and strength of the feedback signal. The proposed flexible PVDF-TrFE based sensor will have a broader application prospect in the fields of light and thin electronic products and multifunction integration of display screens.