Liquid Lens‐Based Optical Tactile Sensor with a Touch‐Sensing Separable Structure

Abstract

Optical tactile sensing plays an important role in the tactile sensing field, due to its high sensitivity, fast response, and prominent interference immunity. Herein, based on the liquid lens, a low‐cost optical tactile sensor with a touch‐sensing separable structure is designed and fabricated, and it contains a touch unit and an optics sensing unit. The touch unit is a chamber structure with good integration, and the optics sensing unit is designed with a liquid‐membrane structure. Different from the existed optical tactile sensors, the principle of the proposed sensor is that the focal length of the optics sensing unit is changed with an external contact force, and then the directional light propagation direction produces change, which affects the perceived light intensity of the silicon photocell. From the sensing performance test results, this tactile sensor has good statics and dynamics performance, which embodies in the rapid response time (about 0.048 s), stable output, high sensitivity (the max sensitivity is about 7.1338 V/N), and resolution (0.01 N), low hysteresis ratio (less than 6.5%), and good linearity (R2 ≈ 0.98). In addition, some application experiments are conducted and the results demonstrate the application feasibility of the proposed sensor in health monitoring and multichannel sensing.

Tunable Liquid Lenses: Emerging Technologies and Future Perspectives

“…The applications of liquid lenses have been extensively explored, including tunable display, [ 218,219 ] imaging, [ 220 ] and other systems. [ 221 ] At present, to our best knowledge, liquid lenses have been integrated with some optical instruments or equipment, forming products with new functions.…”

All‐Printed Finger‐Inspired Tactile Sensor Array for Microscale Texture Detection and 3D Reconstruction

“…The fundamental aspect of tactile detection is its sensitivity to diverse mechanical stimuli from the surroundings, such as pressure, bending, tapping, slipping, and vibration. Tactile sensors have been developed to convert mechanical stimuli into electrical signals by employing different physical transduction mechanisms, including piezoresistivity, [ 33 , 34 , 35 , 36 ] capacitance, [ 37 , 38 , 39 , 40 ] piezoelectricity, [ 41 , 42 , 43 , 44 ] triboelectricity, [ 45 , 46 , 47 , 48 ] acoustics, [ 49 , 50 , 51 ] optics, [ 52 , 53 , 54 ] and magnetism. [ 55 , 56 , 57 ] Because the sensitivity of a tactile sensor is pivotal for accurate texture detection, researchers have sought to enhance it by designing various microstructures, such as pillars, [ 58 , 59 , 60 , 61 ] pyramids, [ 62 , 63 , 64 , 65 ] and hemispheres.…”

Research on a flexible optical tactile sensor based on a liquid lens structure

“…As one of the necessary sensory information in the process of man-machine-environment interaction, tactile information can intuitively reflect the interaction state among the three, and it can ensure the accuracy and stability of interactive tasks (such as remote operation, man-machine collaborative operation, etc.). Sex and security play a key role [1][2][3] . The main way to obtain tactile information is tactile sensors, which enable smart devices to acquire and recognize information such as external contact environment temperature, humidity, shape, pressure, and vibration [4][5][6] , so they are one of the important components of smart devices.…”

“…The composition of optical tactile sensors based on optical imaging is generally more complex, generally composed of cameras, lenses, elastic contacts, light sources, and rigid housings, which have limitations such as high cost and difficulty in miniaturization, so it is difficult to apply them to smart devices. An optical tactile sensor based on optical conduction, this talk aims, based on the previous research foundation of the research group on the tactile perception of liquid lens 1,18,19 , to improve the sensing structure, a smaller size and more compact structure is designed and manufactured. , a more integrated optical tactile sensing system; through the design and construction of a tactile perception performance test platform, and then tested its static and dynamic perception performance; through the designcarried out a weighing application demonstration experiment, explore It shows the application possibility of this optical tactile sensing system in the fields of intelligent interactive devices and smart wearable devices.…”