G. Sessler - Academia.edu (original) (raw)
Papers by G. Sessler
9th International Symposium on Electrets (ISE 9) Proceedings
Based on thermally-stimulated current (TSC), laser-induced pressure pulse (LIPP), and isothermal ... more Based on thermally-stimulated current (TSC), laser-induced pressure pulse (LIPP), and isothermal charge decay (ICD) measurements of PET films in various stages of production, we discuss charge accumulation and dipole orientation introduced by the production process and subsequent positive or negative corona charging of such PET films. In the p r e f h and in the final films, negative charge is more stable than positive charge. Negative charge is generally injected into both sample surfaces by a pinning process and by contact electrification during the production process, where the film is running over metal arid other rollers. The TSC depolarization temperatures are about 80°C for the polarization, 90 to 130°C for positive charges and 110 to 140°C for negative charges.
2008 13th International Symposium on Electrets, 2008
ABSTRACT
2005 12th International Symposium on Electrets
IEEE Transactions on Audio and Electroacoustics, 1971
ABSTRACT
IEEE Transactions on Communications, 1973
A new touch actuator is described that consists of a single metalized foil electret, a number of ... more A new touch actuator is described that consists of a single metalized foil electret, a number of independent metal backplate sections aligned with the holes of a front cover, and air gaps separating electret and backplate sections. The metal layer of the foil forms a transducer with capacitance Cawith each backplate section. The actuator is operated by touching the foil electret through one of the front-cover holes. For a trapezoidal displacement (duration2T) of the foil electret, the electrical output signal across a terminating resistorRconsists of a pair of oppositely poled spikes with duration comparable to RCa, if RCais smaller thanT. If RCais larger thanT, the electrical output approximates the displacement. For an electret with a charge density of10^{-8} C/cm^{2}, the measured pulse amplitudes due to touching are of the order of 0.3 to over 100 V depending on the applied force, and on the resistive and capacitive loading. The touch actuator is mechanically simple, reliable to use, inexpensive to produce, and can be made with an overall thickness of less than 0.5 cm. Apart from its potential use in telephone dials, it may also find applications as a key transducer in digital devices.
IEEE ASSP Magazine, 1984
About 15 years ago, the science and technology of electroacoustic transducers appeared to be matu... more About 15 years ago, the science and technology of electroacoustic transducers appeared to be mature fields, with only minor additions and improvements on the horizon. In the meantime, however, a number of unexpected and significant new developments have taken place in this area of acoustics. As a result, electroacoustic transducers present themselves today in a very new and different fashion. Some of the innovations were, not surprisingly, brought about by communications technology. Examples are the invention of fiber-optic and silicon transducers. Other changes originated directly within the field of electroacoustics. Most prominent among these are the introduction of piezoelectric polymer devices and the wide utilization of polymer-electret transducers. Within each of the above-mentioned groups, most of the attention has focused on microphones, nowadays often referred to as acoustic sensors. In comparison, progress in the field of sound-transmitting devices has been more gradual and, with the exception of some polymer devices, along the traditional lines of acoustic transduction. Another significant aspect of the progress in the transducer field is that many developments were only possible because of advances in the material sciences. This includes not only the introduction of new materials and the better characterization of existing ones, but also the emergence of vastly improved material-processing capabilities. In the present paper, some of the interesting work that originated from the conception of transducers of the fiber-optic, silicon, piezopolymer, and electret varieties is reviewed. In particular, typical representatives of each of these groups are described and their advantages and limitations are discussed. To make the causes for progress in the field of electroacoustic transduction more visible, a few of the corresponding innovations in the material sciences are also analyzed. At the end of each section, a brief outlook on the future of the particular - - kind of transducer is ventured.
Proceedings of IEEE Conference on Electrical Insulation and Dielectric Phenomena - (CEIDP'94)
ABSTRACT
Radiation Physics and Chemistry (1977), 1984
Recently developed methods for charging and investigating polymer electrets are described and dis... more Recently developed methods for charging and investigating polymer electrets are described and discussed in view of their use for the characterization of the respective sample material. Surface charging with electron beams of relatively low energies may be used to achieve positive charging and to determine the secondary-electron emission yield of the specimen. Laser-induced pressure pulses permit the scanning of charge and polarization profiles as well as the measurement of ultrasonic velocity and attenuation. Poling of piezoelectric polymer electrets may be performed by several techniques including electron-beam charging which leads to polarization zones of predetermined thickness inside the samples; poling-current measurements can be utilized to estimate the ferroelectric polarization in the samples and to model the feroelectric-switching behavior of the dipoles.
Proceedings of 8th International Symposium on Electrets (ISE 8)
Proceedings of 1995 Conference on Electrical Insulation and Dielectric Phenomena, 1995
Due to their internal charges, electrets provide a variety of effects such as external fields, ge... more Due to their internal charges, electrets provide a variety of effects such as external fields, generation of forces, and more. Based on these effects electrets are an important component in many applications in the field of sensors and actuators. At present, research is carried out on micromachined devices manufactured completely with the standard steps of silicon technology. Therefore the electret properties of some silicon based inorganic dielectrics have been investigated with different methods which will be described briefly. In addition the mechanical properties of the electret layers have been considered. According to the experimental results which will be reported and discussed, double layers of silicon dioxide and nitride demonstrate improved properties compared to well investigated single layers. Therefore these seem to be interesting electret materials for applications in micromechanical devices.
Proceedings of 1995 Conference on Electrical Insulation and Dielectric Phenomena
ABSTRACT
Physical Review Letters, 1966
Physical Review Letters, 1977
ABSTRACT
Medical Engineering & Physics, 2002
The thermally stimulated discharge (TSD) method, intended for the analysis of charged dielectrics... more The thermally stimulated discharge (TSD) method, intended for the analysis of charged dielectrics, was used for human blood research. Above-room-temperature TSD spectra of blood consist of three peaks. There are indications that the low-temperature peak (40-50 degrees C) corresponds to the thermally stimulated destruction of hydrate shells surrounding blood components while the mid-temperature peak (70-90 degrees C) is related to thermal denaturation of blood proteins. The intensive high-temperature peak (105-120 degrees C) is observed when a phase transition of blood, accompanied by the formation of a firm dry film of blood, occurs. The position of the high-temperature peak depends on the blood group. Data is discussed which suggests that the spontaneous "quasi-electret effect" of blood relates to the character of the biochemical processes taking place in human organisms. The TSD method might be used as simple and informative means of diagnostics in cooperation with medical and physical investigations.
9th International Symposium on Electrets (ISE 9) Proceedings
Based on thermally-stimulated current (TSC), laser-induced pressure pulse (LIPP), and isothermal ... more Based on thermally-stimulated current (TSC), laser-induced pressure pulse (LIPP), and isothermal charge decay (ICD) measurements of PET films in various stages of production, we discuss charge accumulation and dipole orientation introduced by the production process and subsequent positive or negative corona charging of such PET films. In the p r e f h and in the final films, negative charge is more stable than positive charge. Negative charge is generally injected into both sample surfaces by a pinning process and by contact electrification during the production process, where the film is running over metal arid other rollers. The TSC depolarization temperatures are about 80°C for the polarization, 90 to 130°C for positive charges and 110 to 140°C for negative charges.
2008 13th International Symposium on Electrets, 2008
ABSTRACT
2005 12th International Symposium on Electrets
IEEE Transactions on Audio and Electroacoustics, 1971
ABSTRACT
IEEE Transactions on Communications, 1973
A new touch actuator is described that consists of a single metalized foil electret, a number of ... more A new touch actuator is described that consists of a single metalized foil electret, a number of independent metal backplate sections aligned with the holes of a front cover, and air gaps separating electret and backplate sections. The metal layer of the foil forms a transducer with capacitance Cawith each backplate section. The actuator is operated by touching the foil electret through one of the front-cover holes. For a trapezoidal displacement (duration2T) of the foil electret, the electrical output signal across a terminating resistorRconsists of a pair of oppositely poled spikes with duration comparable to RCa, if RCais smaller thanT. If RCais larger thanT, the electrical output approximates the displacement. For an electret with a charge density of10^{-8} C/cm^{2}, the measured pulse amplitudes due to touching are of the order of 0.3 to over 100 V depending on the applied force, and on the resistive and capacitive loading. The touch actuator is mechanically simple, reliable to use, inexpensive to produce, and can be made with an overall thickness of less than 0.5 cm. Apart from its potential use in telephone dials, it may also find applications as a key transducer in digital devices.
IEEE ASSP Magazine, 1984
About 15 years ago, the science and technology of electroacoustic transducers appeared to be matu... more About 15 years ago, the science and technology of electroacoustic transducers appeared to be mature fields, with only minor additions and improvements on the horizon. In the meantime, however, a number of unexpected and significant new developments have taken place in this area of acoustics. As a result, electroacoustic transducers present themselves today in a very new and different fashion. Some of the innovations were, not surprisingly, brought about by communications technology. Examples are the invention of fiber-optic and silicon transducers. Other changes originated directly within the field of electroacoustics. Most prominent among these are the introduction of piezoelectric polymer devices and the wide utilization of polymer-electret transducers. Within each of the above-mentioned groups, most of the attention has focused on microphones, nowadays often referred to as acoustic sensors. In comparison, progress in the field of sound-transmitting devices has been more gradual and, with the exception of some polymer devices, along the traditional lines of acoustic transduction. Another significant aspect of the progress in the transducer field is that many developments were only possible because of advances in the material sciences. This includes not only the introduction of new materials and the better characterization of existing ones, but also the emergence of vastly improved material-processing capabilities. In the present paper, some of the interesting work that originated from the conception of transducers of the fiber-optic, silicon, piezopolymer, and electret varieties is reviewed. In particular, typical representatives of each of these groups are described and their advantages and limitations are discussed. To make the causes for progress in the field of electroacoustic transduction more visible, a few of the corresponding innovations in the material sciences are also analyzed. At the end of each section, a brief outlook on the future of the particular - - kind of transducer is ventured.
Proceedings of IEEE Conference on Electrical Insulation and Dielectric Phenomena - (CEIDP'94)
ABSTRACT
Radiation Physics and Chemistry (1977), 1984
Recently developed methods for charging and investigating polymer electrets are described and dis... more Recently developed methods for charging and investigating polymer electrets are described and discussed in view of their use for the characterization of the respective sample material. Surface charging with electron beams of relatively low energies may be used to achieve positive charging and to determine the secondary-electron emission yield of the specimen. Laser-induced pressure pulses permit the scanning of charge and polarization profiles as well as the measurement of ultrasonic velocity and attenuation. Poling of piezoelectric polymer electrets may be performed by several techniques including electron-beam charging which leads to polarization zones of predetermined thickness inside the samples; poling-current measurements can be utilized to estimate the ferroelectric polarization in the samples and to model the feroelectric-switching behavior of the dipoles.
Proceedings of 8th International Symposium on Electrets (ISE 8)
Proceedings of 1995 Conference on Electrical Insulation and Dielectric Phenomena, 1995
Due to their internal charges, electrets provide a variety of effects such as external fields, ge... more Due to their internal charges, electrets provide a variety of effects such as external fields, generation of forces, and more. Based on these effects electrets are an important component in many applications in the field of sensors and actuators. At present, research is carried out on micromachined devices manufactured completely with the standard steps of silicon technology. Therefore the electret properties of some silicon based inorganic dielectrics have been investigated with different methods which will be described briefly. In addition the mechanical properties of the electret layers have been considered. According to the experimental results which will be reported and discussed, double layers of silicon dioxide and nitride demonstrate improved properties compared to well investigated single layers. Therefore these seem to be interesting electret materials for applications in micromechanical devices.
Proceedings of 1995 Conference on Electrical Insulation and Dielectric Phenomena
ABSTRACT
Physical Review Letters, 1966
Physical Review Letters, 1977
ABSTRACT
Medical Engineering & Physics, 2002
The thermally stimulated discharge (TSD) method, intended for the analysis of charged dielectrics... more The thermally stimulated discharge (TSD) method, intended for the analysis of charged dielectrics, was used for human blood research. Above-room-temperature TSD spectra of blood consist of three peaks. There are indications that the low-temperature peak (40-50 degrees C) corresponds to the thermally stimulated destruction of hydrate shells surrounding blood components while the mid-temperature peak (70-90 degrees C) is related to thermal denaturation of blood proteins. The intensive high-temperature peak (105-120 degrees C) is observed when a phase transition of blood, accompanied by the formation of a firm dry film of blood, occurs. The position of the high-temperature peak depends on the blood group. Data is discussed which suggests that the spontaneous "quasi-electret effect" of blood relates to the character of the biochemical processes taking place in human organisms. The TSD method might be used as simple and informative means of diagnostics in cooperation with medical and physical investigations.