Most of traditional traveling wave piezoelectric transducers are driven by two phase different excitation signals,leading to a complex control system and seriously limiting their applications in industry.To overcome t...Most of traditional traveling wave piezoelectric transducers are driven by two phase different excitation signals,leading to a complex control system and seriously limiting their applications in industry.To overcome these issues,a novel traveling wave sandwich piezoelectric transducer with a single-phase drive is proposed in this study.Traveling waves are produced in two driving rings of the transducer while the longitudinal vibration is excited in its sandwich composite beam,due to the coupling property of the combined structure.This results in the production of elliptical motions in the two driving rings to achieve the drive function.An analytical model is firstly developed using the transfer matrix method to analyze the dynamic behavior of the proposed transducer.Its vibration characteristics are measured and compared with computational results to validate the effectiveness of the proposed analytical model.Besides,the driving concept of the transducer is investigated by computing the motion trajectory of surface points of the driving ring and the quality of traveling wave of the driving ring.Additionally,application example investigations on the driving effect of the proposed transducer are carried out by constructing and assembling a tracked mobile system.Experimental results indicated that 1)the assembled tracked mobile system moved in the driving frequency of 19410 Hz corresponding to its maximum mean velocity through frequency sensitivity experiments;2)motion characteristic and traction performance measurements of the system prototype presented its maximum mean velocity with 59 mm/s and its maximum stalling traction force with 1.65 N,at the excitation voltage of 500 V_(RMS).These experimental results demonstrate the feasibility of the proposed traveling wave sandwich piezoelectric transducer.展开更多
Organic light-emitting diodes(OLEDs)used in virtual and augmented reality displays require micrometer-scale red-green-blue(RGB)pixel patterns in the emissive layer(EML).However,conventional patterning methods based on...Organic light-emitting diodes(OLEDs)used in virtual and augmented reality displays require micrometer-scale red-green-blue(RGB)pixel patterns in the emissive layer(EML).However,conventional patterning methods based on evaporation and shadow masks can only produce patterns larger than tens of micrometers owing to the geometric constraint of the mask.Herein,an indirect method for photopatterning solution-processed OLED EMLs is proposed,which can be used to form micrometer-scale RGB pixel patterns without involving direct exposure to UV radiation or harsh etching processes on EMLs.EMLs can be patterned byⅰ)forming a sacrificial photoresist(PR)pattern,ⅱ)spin-coating an EML film,ⅲ)converting the EML film into a single-phase network(SPN)structure by crosslinking vinylbenzyl-group-appended hosts and dopants at a low temperature,andⅳ)stripping the pre-formed PR pattern.Furthermore,repeating the process thrice results in the formation of RGB EML patterns.During the repeated process,the sacrificial PR pattern serves as a protective layer for the underlying EML pattern,effectively preventing the EML pattern from being exposed to solutions in subsequent processes.Using a conventional photolithography setup,we produced sets of RGB EML patterns with densities exceeding 3000 patterns/in.,which indicated the potential of the method for industrial use.展开更多
基金Supported by the National Science Foundation of China(Grants Nos.51905262 and U2037603)the Natural Science Foundation of Jiangsu Province(Grant No.BK20190398)the State Key Laboratory of Mechanical System and Vibration(Grant No.MSV202011).
文摘Most of traditional traveling wave piezoelectric transducers are driven by two phase different excitation signals,leading to a complex control system and seriously limiting their applications in industry.To overcome these issues,a novel traveling wave sandwich piezoelectric transducer with a single-phase drive is proposed in this study.Traveling waves are produced in two driving rings of the transducer while the longitudinal vibration is excited in its sandwich composite beam,due to the coupling property of the combined structure.This results in the production of elliptical motions in the two driving rings to achieve the drive function.An analytical model is firstly developed using the transfer matrix method to analyze the dynamic behavior of the proposed transducer.Its vibration characteristics are measured and compared with computational results to validate the effectiveness of the proposed analytical model.Besides,the driving concept of the transducer is investigated by computing the motion trajectory of surface points of the driving ring and the quality of traveling wave of the driving ring.Additionally,application example investigations on the driving effect of the proposed transducer are carried out by constructing and assembling a tracked mobile system.Experimental results indicated that 1)the assembled tracked mobile system moved in the driving frequency of 19410 Hz corresponding to its maximum mean velocity through frequency sensitivity experiments;2)motion characteristic and traction performance measurements of the system prototype presented its maximum mean velocity with 59 mm/s and its maximum stalling traction force with 1.65 N,at the excitation voltage of 500 V_(RMS).These experimental results demonstrate the feasibility of the proposed traveling wave sandwich piezoelectric transducer.
基金supported by the National R&D Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Science and ICT(NRF-2023R1A2C3006550,2021R1A2C2008332,and RS-2024-00445116)。
文摘Organic light-emitting diodes(OLEDs)used in virtual and augmented reality displays require micrometer-scale red-green-blue(RGB)pixel patterns in the emissive layer(EML).However,conventional patterning methods based on evaporation and shadow masks can only produce patterns larger than tens of micrometers owing to the geometric constraint of the mask.Herein,an indirect method for photopatterning solution-processed OLED EMLs is proposed,which can be used to form micrometer-scale RGB pixel patterns without involving direct exposure to UV radiation or harsh etching processes on EMLs.EMLs can be patterned byⅰ)forming a sacrificial photoresist(PR)pattern,ⅱ)spin-coating an EML film,ⅲ)converting the EML film into a single-phase network(SPN)structure by crosslinking vinylbenzyl-group-appended hosts and dopants at a low temperature,andⅳ)stripping the pre-formed PR pattern.Furthermore,repeating the process thrice results in the formation of RGB EML patterns.During the repeated process,the sacrificial PR pattern serves as a protective layer for the underlying EML pattern,effectively preventing the EML pattern from being exposed to solutions in subsequent processes.Using a conventional photolithography setup,we produced sets of RGB EML patterns with densities exceeding 3000 patterns/in.,which indicated the potential of the method for industrial use.
