Elektret davranışları ve uygulamaları
Electret behaviours and its applications
- Tez No: 39804
- Danışmanlar: Y.DOÇ.DR. ÖZCAN KALENDERLİ
- Tez Türü: Yüksek Lisans
- Konular: Elektrik ve Elektronik Mühendisliği, Electrical and Electronics Engineering
- Anahtar Kelimeler: Belirtilmemiş.
- Yıl: 1994
- Dil: Türkçe
- Üniversite: İstanbul Teknik Üniversitesi
- Enstitü: Fen Bilimleri Enstitüsü
- Ana Bilim Dalı: Belirtilmemiş.
- Bilim Dalı: Belirtilmemiş.
- Sayfa Sayısı: 108
Özet
Information about the distribution -of charge and polarization in the thickness direction of thin polymer films can now be readly obtained with pressure - pulse experiments. One such technique, the laser Induced pressure - pulse (LIPP) method, has been used in the past to investigate charge layers in FEP films metalized on both surfaces and charged with electron beams of various energies through the foating front electrode. These measurements showed the presence of a major charge layer located at a depth corresponding to the range of electrons. Recent LIPP studies of one - side metalized PETP and PI, charged with an electron beam through the non - metalized surface, indicate the existence of charge distributions consisting of a surface - charge layer and a volume charge layer. 5. ELECTRET APPLICATIONS Only a few exemplary electret applications which were studied duriing the last few years are given; the examples chosen should give an impression of the wide range of possibilities that electrets present to the applications engineer. 5.1. AN ELECTRET SWITCH Electrets were fabricated from Teflon - FEP film of 12 p.m in thickness by heating to 140 C° and charging the surface by corona. The attractive force Fa and the repulsive force Fr acting on the movable electrode due to the charge on the surface of the electret were measured using models of the vertical movement system and the hinge movement system, as a function of stroke. Decay of the charge on the surface on the one - side- surface metalized film. The attractive force obtained from the hinge movement system was Fa = 3.5 mN when the surface charge density a = 1.8 x 10-8 C/cm2, the facing area of the movable electrode S = 4.8 cm2, the stroke d = 0.1 mm and driving voltage V0 = 100 V and the attractive force obtained from the vertical movement system was 2.5 mN under the same conditions [13]. 5.2. AN AIR FILTER FROM AN ELECTRET AND A CONDUCTOR Electrically charged filter fibers and in particular, electret fibers, can be used in air filters. Planar electrets have a high internal and a low external electric field; but only external fields contribute to filtration and so if electrets are used in filters, the fundamental problem is to increase the external field. In a conventional electret filter this problem is solved simply by reducing the width of the electret sheet by making it into fibers, but an alternative solution is to place conductors close to the surface of the electret. The total charge on such a filter has been measured microscopically by X - irradiation and macroscopically with a probe; the two methods give similar results. The electric field inside the filter has been calculated by a self - consistent method [14]. 5.3. THEORETICAL CHARACTERISTICS OF GENERALIZED ELECTRET GENERATOR, USING POLYMER FILM ELECTRETS. The rotor of the generator consists of a conducting disk and several fan - shaped pieces of two types film electret, attached to the conducting disk with holes that have the same fan - shape as the electret. The generator has a slip ring and a XII
Özet (Çeviri)
SUMMARY ELECTRET BEHAVIOURS AND ITS APPLICATIONS 1.ELECTRET It is possible, to inject charge into certain dielectrics by heating to a high enough temperature and subsequently cooling in the presence of an electric field, and the charge frozen in by this method can be stable for several years, such a permanently charged dielectric is called an electret. The internal field distribution of an electret, when a voltage is applied, is determined by both the electrode configuration and by the charge of electret. 2. ELECTRET RESEARCH - STAGES IN ITS DEVELOPMENT Greek philosophers, notably Thales of Milet, Plato, Aristotle are reported to have known about the attracting forces of rubbed amber, Around 1600, William Gilbert defined“ electrica, quae attraunt eadem ratione ut electrum ”(electrics which attract in the same way as amber) and gave several examples of such materials. During the next three centuries, electric charges on insulating materials were studied by a large number of scientists. One of the them was Stephen Gray who, in 1732, described the production of“electric bodies”from resin, pitch, shellac and suffer by means of melting and cooling. The second half of the eighteenth century saw the introduction of the so called“electrophorus ”(electricity carrier), which was independently contributions were, however made by Michael Faraday who still used the term electrics for insulating materials.but also introduced the new word“dielectric”in 1838. Modern electret research started in Japan with the pioneering work Mototaro Eguchi who still used the term“electrophorus”in his first study (1919) and only later switched to Heaviside's word“electret”though his wax electrets probably contained real charges as well as dipols. Eguchi' s broader definition is generally accepted today. Incidentally, the now obsolete historical term electrophorus is less specific than the word“electret”and would thus describe the wide variety of modern electret phenomena more accurately in 1945's was reviewed by Gutman in 1948. An excellent and comprehensive bibliographical review of electret papers published until 1965 is found in a book by Bernhard Gross. A brief survey of electret research from 1732 to 1972 was given by Oleg Jefimenko in 1973 [1-12]. Today, electret research is very active and the wealth of publications becomes more and more diffucult to assess. VIIInformation about the distribution -of charge and polarization in the thickness direction of thin polymer films can now be readly obtained with pressure - pulse experiments. One such technique, the laser Induced pressure - pulse (LIPP) method, has been used in the past to investigate charge layers in FEP films metalized on both surfaces and charged with electron beams of various energies through the foating front electrode. These measurements showed the presence of a major charge layer located at a depth corresponding to the range of electrons. Recent LIPP studies of one - side metalized PETP and PI, charged with an electron beam through the non - metalized surface, indicate the existence of charge distributions consisting of a surface - charge layer and a volume charge layer. 5. ELECTRET APPLICATIONS Only a few exemplary electret applications which were studied duriing the last few years are given; the examples chosen should give an impression of the wide range of possibilities that electrets present to the applications engineer. 5.1. AN ELECTRET SWITCH Electrets were fabricated from Teflon - FEP film of 12 p.m in thickness by heating to 140 C° and charging the surface by corona. The attractive force Fa and the repulsive force Fr acting on the movable electrode due to the charge on the surface of the electret were measured using models of the vertical movement system and the hinge movement system, as a function of stroke. Decay of the charge on the surface on the one - side- surface metalized film. The attractive force obtained from the hinge movement system was Fa = 3.5 mN when the surface charge density a = 1.8 x 10-8 C/cm2, the facing area of the movable electrode S = 4.8 cm2, the stroke d = 0.1 mm and driving voltage V0 = 100 V and the attractive force obtained from the vertical movement system was 2.5 mN under the same conditions [13]. 5.2. AN AIR FILTER FROM AN ELECTRET AND A CONDUCTOR Electrically charged filter fibers and in particular, electret fibers, can be used in air filters. Planar electrets have a high internal and a low external electric field; but only external fields contribute to filtration and so if electrets are used in filters, the fundamental problem is to increase the external field. In a conventional electret filter this problem is solved simply by reducing the width of the electret sheet by making it into fibers, but an alternative solution is to place conductors close to the surface of the electret. The total charge on such a filter has been measured microscopically by X - irradiation and macroscopically with a probe; the two methods give similar results. The electric field inside the filter has been calculated by a self - consistent method [14]. 5.3. THEORETICAL CHARACTERISTICS OF GENERALIZED ELECTRET GENERATOR, USING POLYMER FILM ELECTRETS. The rotor of the generator consists of a conducting disk and several fan - shaped pieces of two types film electret, attached to the conducting disk with holes that have the same fan - shape as the electret. The generator has a slip ring and a XIIbrush. The generator becomes non - parametric when the two types of electret of the rotor have the same permittivity and thickness and parametric when the two electret different.[15]. 5.4. SUBMINIATURE SILICON INTEGRATED ELECTRET CAPASITOR MICROPHONE. Silicon micromachining provides better precision for controlling diaphragm - backplate spacing in electret microphones than more classical techniques. The silicon support members can also be used to carry the IC amplifier which is usually required for impedance matching. Microphones which use one silicon wafer to support a thin polyester diaphragm and a second to carry a Teflon or silicon dioxide electret has been prepared subassemblies are diced from the wafer and bonded together to form complete microphones. The preamplifier circuit can be carried on either subassembly. Microphones with reasonable signal - to - noise ratio can be obtained with edge dimensions of 3 mm or less. The fundamentel characteristics of the generators are very similar and the output voltage, current and power of the non - parametric generator are larger than those of the parametric generator under the same conditions. The output voltages and currents of both generators are proportional to a lineer combination of the surface charge densities of the two electrets. Based on these results, the electret switches were fabricated by way of trial; variations of the operating voltage and the return voltage were suppressed below 30 % when the switches were driven with Vc = 150 V applied and cycled about one million [16]. 5.5. CONCLUSIONS Today, electret researchs are very active and the wealth of publications becomes more and more difficult to assess. During the last two decades, piezo, pyro, and ferro - electric polymer electrets, often consisting of poly(vinylidene fluoride) or one of its copolymers, became important in science and technology ; today, this field is established and very active. Recently, the relatively dormant subject of charge storage in inorganic materials was taken up by a nummer of researchers probably because the basic proporties of these materials are often quite well understood and also because their application in integrated electret sensors promises inexpensive large - scale production of such devices. Polymer electrets are now entering the exciting hew fields of non - linear optics, opto - electronics, and integrated optics, which were so far dominated by inorganic materials XIIIInformation about the distribution -of charge and polarization in the thickness direction of thin polymer films can now be readly obtained with pressure - pulse experiments. One such technique, the laser Induced pressure - pulse (LIPP) method, has been used in the past to investigate charge layers in FEP films metalized on both surfaces and charged with electron beams of various energies through the foating front electrode. These measurements showed the presence of a major charge layer located at a depth corresponding to the range of electrons. Recent LIPP studies of one - side metalized PETP and PI, charged with an electron beam through the non - metalized surface, indicate the existence of charge distributions consisting of a surface - charge layer and a volume charge layer. 5. ELECTRET APPLICATIONS Only a few exemplary electret applications which were studied duriing the last few years are given; the examples chosen should give an impression of the wide range of possibilities that electrets present to the applications engineer. 5.1. AN ELECTRET SWITCH Electrets were fabricated from Teflon - FEP film of 12 p.m in thickness by heating to 140 C° and charging the surface by corona. The attractive force Fa and the repulsive force Fr acting on the movable electrode due to the charge on the surface of the electret were measured using models of the vertical movement system and the hinge movement system, as a function of stroke. Decay of the charge on the surface on the one - side- surface metalized film. The attractive force obtained from the hinge movement system was Fa = 3.5 mN when the surface charge density a = 1.8 x 10-8 C/cm2, the facing area of the movable electrode S = 4.8 cm2, the stroke d = 0.1 mm and driving voltage V0 = 100 V and the attractive force obtained from the vertical movement system was 2.5 mN under the same conditions [13]. 5.2. AN AIR FILTER FROM AN ELECTRET AND A CONDUCTOR Electrically charged filter fibers and in particular, electret fibers, can be used in air filters. Planar electrets have a high internal and a low external electric field; but only external fields contribute to filtration and so if electrets are used in filters, the fundamental problem is to increase the external field. In a conventional electret filter this problem is solved simply by reducing the width of the electret sheet by making it into fibers, but an alternative solution is to place conductors close to the surface of the electret. The total charge on such a filter has been measured microscopically by X - irradiation and macroscopically with a probe; the two methods give similar results. The electric field inside the filter has been calculated by a self - consistent method [14]. 5.3. THEORETICAL CHARACTERISTICS OF GENERALIZED ELECTRET GENERATOR, USING POLYMER FILM ELECTRETS. The rotor of the generator consists of a conducting disk and several fan - shaped pieces of two types film electret, attached to the conducting disk with holes that have the same fan - shape as the electret. The generator has a slip ring and a XIIbrush. The generator becomes non - parametric when the two types of electret of the rotor have the same permittivity and thickness and parametric when the two electret different.[15]. 5.4. SUBMINIATURE SILICON INTEGRATED ELECTRET CAPASITOR MICROPHONE. Silicon micromachining provides better precision for controlling diaphragm - backplate spacing in electret microphones than more classical techniques. The silicon support members can also be used to carry the IC amplifier which is usually required for impedance matching. Microphones which use one silicon wafer to support a thin polyester diaphragm and a second to carry a Teflon or silicon dioxide electret has been prepared subassemblies are diced from the wafer and bonded together to form complete microphones. The preamplifier circuit can be carried on either subassembly. Microphones with reasonable signal - to - noise ratio can be obtained with edge dimensions of 3 mm or less. The fundamentel characteristics of the generators are very similar and the output voltage, current and power of the non - parametric generator are larger than those of the parametric generator under the same conditions. The output voltages and currents of both generators are proportional to a lineer combination of the surface charge densities of the two electrets. Based on these results, the electret switches were fabricated by way of trial; variations of the operating voltage and the return voltage were suppressed below 30 % when the switches were driven with Vc = 150 V applied and cycled about one million [16]. 5.5. CONCLUSIONS Today, electret researchs are very active and the wealth of publications becomes more and more difficult to assess. During the last two decades, piezo, pyro, and ferro - electric polymer electrets, often consisting of poly(vinylidene fluoride) or one of its copolymers, became important in science and technology ; today, this field is established and very active. Recently, the relatively dormant subject of charge storage in inorganic materials was taken up by a nummer of researchers probably because the basic proporties of these materials are often quite well understood and also because their application in integrated electret sensors promises inexpensive large - scale production of such devices. Polymer electrets are now entering the exciting hew fields of non - linear optics, opto - electronics, and integrated optics, which were so far dominated by inorganic materials XIIIInformation about the distribution -of charge and polarization in the thickness direction of thin polymer films can now be readly obtained with pressure - pulse experiments. One such technique, the laser Induced pressure - pulse (LIPP) method, has been used in the past to investigate charge layers in FEP films metalized on both surfaces and charged with electron beams of various energies through the foating front electrode. These measurements showed the presence of a major charge layer located at a depth corresponding to the range of electrons. Recent LIPP studies of one - side metalized PETP and PI, charged with an electron beam through the non - metalized surface, indicate the existence of charge distributions consisting of a surface - charge layer and a volume charge layer. 5. ELECTRET APPLICATIONS Only a few exemplary electret applications which were studied duriing the last few years are given; the examples chosen should give an impression of the wide range of possibilities that electrets present to the applications engineer. 5.1. AN ELECTRET SWITCH Electrets were fabricated from Teflon - FEP film of 12 p.m in thickness by heating to 140 C° and charging the surface by corona. The attractive force Fa and the repulsive force Fr acting on the movable electrode due to the charge on the surface of the electret were measured using models of the vertical movement system and the hinge movement system, as a function of stroke. Decay of the charge on the surface on the one - side- surface metalized film. The attractive force obtained from the hinge movement system was Fa = 3.5 mN when the surface charge density a = 1.8 x 10-8 C/cm2, the facing area of the movable electrode S = 4.8 cm2, the stroke d = 0.1 mm and driving voltage V0 = 100 V and the attractive force obtained from the vertical movement system was 2.5 mN under the same conditions [13]. 5.2. AN AIR FILTER FROM AN ELECTRET AND A CONDUCTOR Electrically charged filter fibers and in particular, electret fibers, can be used in air filters. Planar electrets have a high internal and a low external electric field; but only external fields contribute to filtration and so if electrets are used in filters, the fundamental problem is to increase the external field. In a conventional electret filter this problem is solved simply by reducing the width of the electret sheet by making it into fibers, but an alternative solution is to place conductors close to the surface of the electret. The total charge on such a filter has been measured microscopically by X - irradiation and macroscopically with a probe; the two methods give similar results. The electric field inside the filter has been calculated by a self - consistent method [14]. 5.3. THEORETICAL CHARACTERISTICS OF GENERALIZED ELECTRET GENERATOR, USING POLYMER FILM ELECTRETS. The rotor of the generator consists of a conducting disk and several fan - shaped pieces of two types film electret, attached to the conducting disk with holes that have the same fan - shape as the electret. The generator has a slip ring and a XIIbrush. The generator becomes non - parametric when the two types of electret of the rotor have the same permittivity and thickness and parametric when the two electret different.[15]. 5.4. SUBMINIATURE SILICON INTEGRATED ELECTRET CAPASITOR MICROPHONE. Silicon micromachining provides better precision for controlling diaphragm - backplate spacing in electret microphones than more classical techniques. The silicon support members can also be used to carry the IC amplifier which is usually required for impedance matching. Microphones which use one silicon wafer to support a thin polyester diaphragm and a second to carry a Teflon or silicon dioxide electret has been prepared subassemblies are diced from the wafer and bonded together to form complete microphones. The preamplifier circuit can be carried on either subassembly. Microphones with reasonable signal - to - noise ratio can be obtained with edge dimensions of 3 mm or less. The fundamentel characteristics of the generators are very similar and the output voltage, current and power of the non - parametric generator are larger than those of the parametric generator under the same conditions. The output voltages and currents of both generators are proportional to a lineer combination of the surface charge densities of the two electrets. Based on these results, the electret switches were fabricated by way of trial; variations of the operating voltage and the return voltage were suppressed below 30 % when the switches were driven with Vc = 150 V applied and cycled about one million [16]. 5.5. CONCLUSIONS Today, electret researchs are very active and the wealth of publications becomes more and more difficult to assess. During the last two decades, piezo, pyro, and ferro - electric polymer electrets, often consisting of poly(vinylidene fluoride) or one of its copolymers, became important in science and technology ; today, this field is established and very active. Recently, the relatively dormant subject of charge storage in inorganic materials was taken up by a nummer of researchers probably because the basic proporties of these materials are often quite well understood and also because their application in integrated electret sensors promises inexpensive large - scale production of such devices. Polymer electrets are now entering the exciting hew fields of non - linear optics, opto - electronics, and integrated optics, which were so far dominated by inorganic materials XIII
Benzer Tezler
- Alumina/glass composites for low temperature co-fired ceramics (LTCC) and radome applications
Alümina/cam kompozitlerin düşük sıcaklıkta beraber pişen seramikler (LTCC) ve radom uygulamaları
GÜLSÜM MERYEM DURSUN
Yüksek Lisans
İngilizce
2018
Seramik MühendisliğiAnkara Yıldırım Beyazıt ÜniversitesiPROF. DR. CİHANGİR DURAN
- Politiyofen esaslı Nanokompozit malzeme sentezi, Elektrokimyasal Davranışları ve Süperkapasitör Uygulamaları
Synthesis of polythi̇ophene based nanocomposite materials, electrochemical behaviors and supercapacitor applications
SELDA ALAÇAMLI
Yüksek Lisans
Türkçe
2023
KimyaTekirdağ Namık Kemal ÜniversitesiKimya Ana Bilim Dalı
PROF. DR. MURAT ATEŞ
- Aripiprazol tayini için elektrokimyasal yöntemler geliştirilmesi ve analitik uygulamaları
Aripiprazol tayini için elektrokimyasal yöntemler geliştirilmesi ve analitik uygulamalari
DERYA AŞANGİL
- Politiyofen polimerler ve bunların organik radikal pillerde ve manyetik malzemelerdeki uygulamaları
Polythiophene polymers and their applications in organic radical batteries and magnetic materials
MUHAMMET AYDIN
Yüksek Lisans
Türkçe
2011
Polimer Bilim ve TeknolojisiGebze Yüksek Teknoloji EnstitüsüKimya Ana Bilim Dalı
DOÇ. DR. FARUK YILMAZ
- Doğal karbon kaynaklarından karbon kuantum nokta sentezi: Biyolojik uygulamaları ve DNA duyarlı elektrokimyasal biyosensör geliştirilmesi
Carbon quantum dot synthesis from natural carbon sources: Biological applications and development of DNA-sensitive electrochemical biosensor
SADİYE KÜBRA BAŞKAYA
Doktora
Türkçe
2022
KimyaKahramanmaraş Sütçü İmam ÜniversitesiMalzeme Bilimi ve Mühendisliği Ana Bilim Dalı
DR. ÖĞR. ÜYESİ MUSTAFA ÇEŞME