Paul Braatz - Academia.edu (original) (raw)

Papers by Paul Braatz

Un relais variateur de lumiere a cristaux liquides comporte un substrat de base (20) en saphir, u... more Un relais variateur de lumiere a cristaux liquides comporte un substrat de base (20) en saphir, une couche epitaxiale mince de silicium extremement dopee formant un contact de repos ohmique sur une surface lisse du substrat en saphir, ainsi qu'une couche epitaxiale (4) legerement dopee de silicium a haute resistivite d'une epaisseur de l'ordre de 20 a 60 microns, situee sur le contact de repos. L'utilisation d'un substrat en saphir assure une meilleure qualite de surface et une resolution plus elevee que celles existant precedemment avec les substrats a semi-conducteurs. Les defauts du reseau cristallin dans le contact de repos mince sont reduits par la formation d'une couche amorphe noyee adjacente au substrat en saphir, et sa recristallisation ulterieure en utilisant comme germes de recristallisation les parties non rendues amorphes du contact de repos. Est decrite l'application de l'invention aux relais variateurs de lumiere a cristaux liquides MOS...

: The aim of this program has been to develop the silicon photoconductor liquid crystal light val... more : The aim of this program has been to develop the silicon photoconductor liquid crystal light valve (LCLV) as a second-generation, higher-performance device, as well as to optimize the multimode operation of the liquid crystal. The latter effort was primarily aimed at allowing a full-performance CdS LCLV to be realized, given the switching-ratio limitation of this device, as well as to allow the silicon LCLV, when completed, to fully benefit from this development. This program has resulted in the successful development of a silicon LCLV in which we have solved the edge breakdown effect, developed a novel Si/Si02 dielectric mirror, implemented a focusing-grid to improve resolution and scaled up the device from a 1 cm x 1 cm aperture to a 2 in. aperture device. This has resulted in a fast-response, high switching-ratio device approaching the resolution performance of the CdS light valve. The LC multimode operation has been successfully optimized, resulting in a practical demonstration...

: The development of a new type of large area infrared detector cell with visible light readout i... more : The development of a new type of large area infrared detector cell with visible light readout is studied in which a liquid crystal layer is electro-optically activated by a pyroelectric film. These studies include the evaluation of pyroelectric films and their poling techniques, the evaluation of liquid crystals for use with pyroelectric currents, analysis of thermal time constants in various cell layers, evaluation of signals obtained with test cells, and the development of prototype detectors. Polyvinylidene fluoride (PVF2) is selected as the best large area pyroelectric material available. In operation with 10.6 micrometer laser exposures, the effects of the pyroelectric generated voltage across the liquid crystal are obscured by thermal flow effects. However, a revised design is recommended in which a conductive faceplate is used to thermally isolate the pyroelectric film from the liquid crystal layer.

: During this contract, we accomplished the following major tasks toward the development of a CCD... more : During this contract, we accomplished the following major tasks toward the development of a CCD liquid-crystal light valve. We have demonstrated a fully operational CCD LCLV with a contrast ratio of 50:1 and a spatial resolution of 12 lines across the device. An alternative chip dicing method has been developed that reduces degradation to the substrate by a factor of 100. In addition, a new CCD LCLV packaging technique has been developed that improves the light valve fabrication yield from 30% to 80%. (Author)

L'invention porte sur un procede et sur un detecteur servant a determiner le rapport entre de... more L'invention porte sur un procede et sur un detecteur servant a determiner le rapport entre deux composants d'un melange fluide, comportant une cellule de controle en communication ouverte avec le melange, et une cellule de reference contenant un melange dans les proportions desirees et non en contact avec le melange a controler, les deux cellules presentant la meme geometrie. A l'aide d'un systeme diviseur de capacite, on determine les capacites relatives desdites cellules qui sont correlees avec les constantes dielectriques des differents melanges, et on determine le rapport entre un composant du melange et les autres composants du melange sur la base de correlations lineaires et monotones entre la constante dielectrique du melange a une temperature donnee et du rapport entre un composant du melange et les autres composants. Le melange a controler est de preference un melange de methanol et d'eau servant a alimenter un reformeur fournissant de l'hydrogene a ...

: The basic objective of this program has been to develop a silicon photoconductor liquid crystal... more : The basic objective of this program has been to develop a silicon photoconductor liquid crystal light valve (Si LCLV) for application in wide-field-of-view simulators. The Si LCLV is expected to offer several advantages over the cadmium sulfide (CdS) photoconductor LCLV, including higher sensitivity, a significantly better switching ratio, higher resolution, and (most importantly) a fast response time to allow higher 60-Hz operation. The main thrust of this program was to upgrade the device in the following areas: (1) Scale up to a 2-inch aperture device (from a 1 cm x 1 cm active area). (2) Implement the silicon/silicon dioxide (Si/SiO2) dielectric mirror and improve the light blocking layer. (3) Upgrade device resolution by optimizing the focusing grid. (4) Increase the contrast ratio by improving silicon processing. (5) Implement the dc-biased guard ring to prevent edge breakdown. (6) Optimize liquid crystal operation to reduce the reponse time. Significant improvements were ac...

Spatial Light Modulators and Applications I

ABSTRACT

The Review of Laser Engineering, 1982

Effective Utilization of Optics in Radar Systems, 1977

ABSTRACT

Conductive Polymers and Plastics, 1999

Publisher Summary This chapter discusses the development of conductive polymer-based transducers ... more Publisher Summary This chapter discusses the development of conductive polymer-based transducers for the detection of volatile organic compounds (VOCs) and other gaseous pollutants for application in environmental monitoring. In the experiment described in the chapter, highly sensitive sensor elements derived from polyaniline (PANI) are demonstrated for NO2 and other VOCs. A figure of merit is defined to allow the comparison of the response of different sensors to particular challenge vapors at various concentrations. The use of excess silane coupling agents to modify the surface of the sensor substrates in combination with excess of a sulfonic acid used to convert PANI to its conductive state results in highly sensitive, stable, and reversible VOC sensors, along with some polythiophene derivatives, for the detection of ketones, esters, and aromatic hydrocarbons. Individual sensors show different sensitivities to each class of VOC used in the study so that an array of these sensors generated a characteristic signature for each class demonstrating selectivity and classification.

Integrated Optics and Millimeter and Microwave Integrated Circuits, 1982

ABSTRACT

Optical Engineering, 1983

The structure, operation, and performance of the silicon-based liquid crystal light valves--the p... more The structure, operation, and performance of the silicon-based liquid crystal light valves--the photoactivated, CCD-addressed, and visible-to-IR converter--are described. The performance limitations of the readout structure, in particular those affecting resolution, sensitivity, contrast ratio, and speed, are discussed.

Journal of Power Sources, 2002

Exploratory studies on small plastic lithium-ion battery test cells with improved cathode materia... more Exploratory studies on small plastic lithium-ion battery test cells with improved cathode material show high pulse power capability and outstanding stability both in a 25°C pulse cycling test and in a 55°C calendar life test. Typical discharge pulse power values are 60mW/cm2. After 50,000 pulse cycles at 5C rates, cells at 25°C retain 100% of their initial 1C capacity and 75% of their pulse power capability. After 60 days at 55°C, cells measured at 25°C retain 98% of their initial 1C capacity and 70% of their pulse power capability. This performance is an excellent basis for the development of long life batteries for hybrid vehicles, as shown by a calculated scale up to a 30kW hybrid battery for a “Fast Response Engine”.

Journal of Applied Physics, 1975

ABSTRACT

Applied Physics Letters, 1984

A new method for the direct determination of minority‐carrier lifetime is presented, which utiliz... more A new method for the direct determination of minority‐carrier lifetime is presented, which utilizes transient capacitance measurements performed with varying depletion voltages on metal‐oxide‐semiconductor (MOS) structures. It is shown that the slope of the fill (storage) time versus the depletion voltage is directly proportional to the minority‐carrier lifetime. Good agreement is shown between results obtained with the proposed method and those obtained using a standard technique. The method is limited, however, to low‐doped MOS structures which can be depleted to the back contact.

Un relais optique (5) a deux diodes Schottky comporte un cristal liquide (80) permettant de modul... more Un relais optique (5) a deux diodes Schottky comporte un cristal liquide (80) permettant de moduler localement un faisceau (120) par rotation de la polarisation afin de produire un faisceau module (121), et un photo-conducteur (40) adjacent au cristal liquide (80) et permettant de recevoir et d'absorber un second faisceau (110). Le photo-conducteur (40) commande la polarisation par reaction au contenu optique du second faisceau (110). Le photo-conducteur (40) comprend un substrat a semi-conducteurs et une paire de diodes Schottky (60/40, 30/40) disposees sur les cotes opposes du substrat. L'absorption du second faisceau (110) par le substrat (40) produit des porteurs majoritaires generes par la lumiere. La paire de diodes Schottky (60/40, 30/40) assure l'appauvrissement substantiel du substrat en de tels porteurs et reflechit egalement le faisceau module a travers le cristal liquide.

Journal of Power Sources, 2002

Commercial supercapacitors, also known as ultracapacitors or electrochemical capacitors, from Saf... more Commercial supercapacitors, also known as ultracapacitors or electrochemical capacitors, from Saft, Maxwell, Panasonic, CCR, Ness, EPCOS, and Power Systems were tested under constant current and constant power discharges to assess their applicability for power-assist applications in hybrid electric vehicles (HEVs). Commercial lithium-ion batteries from Saft and Shin-Kobe were also tested under similar conditions. Internal resistances were measured by electrochemical impedance spectroscopy (EIS), as well as by the ''iR drop'' method. Self discharge measurements were also recorded. Compared with earlier generations of supercapacitors, the cells showed improved current and power capability. However, their energy densities are still too low to meet goals set by Partnership for a New Generation of Vehicles (PNGV) for HEV propulsion. Cells that use acetonitrile as the electrolyte solvent yield better performance, although safety issues need to be addressed. New high-power lithium-ion batteries show high energy densities, with high power capabilities.

Journal of applied …, 1985

The silicon liquid-crystal light valve U. Efron, J. Grinberg, PO Braatz, MJ Littfe, PG Reif, and ... more The silicon liquid-crystal light valve U. Efron, J. Grinberg, PO Braatz, MJ Littfe, PG Reif, and R. N. Schwartz Hughes Research Laboratories, Malibu, California 90265 (Received 30 July Î982; accepted for publication 6 My 1984) Detailed description is given of the structure, ...

Un relais variateur de lumiere a cristaux liquides comporte un substrat de base (20) en saphir, u... more Un relais variateur de lumiere a cristaux liquides comporte un substrat de base (20) en saphir, une couche epitaxiale mince de silicium extremement dopee formant un contact de repos ohmique sur une surface lisse du substrat en saphir, ainsi qu'une couche epitaxiale (4) legerement dopee de silicium a haute resistivite d'une epaisseur de l'ordre de 20 a 60 microns, situee sur le contact de repos. L'utilisation d'un substrat en saphir assure une meilleure qualite de surface et une resolution plus elevee que celles existant precedemment avec les substrats a semi-conducteurs. Les defauts du reseau cristallin dans le contact de repos mince sont reduits par la formation d'une couche amorphe noyee adjacente au substrat en saphir, et sa recristallisation ulterieure en utilisant comme germes de recristallisation les parties non rendues amorphes du contact de repos. Est decrite l'application de l'invention aux relais variateurs de lumiere a cristaux liquides MOS...

: The aim of this program has been to develop the silicon photoconductor liquid crystal light val... more : The aim of this program has been to develop the silicon photoconductor liquid crystal light valve (LCLV) as a second-generation, higher-performance device, as well as to optimize the multimode operation of the liquid crystal. The latter effort was primarily aimed at allowing a full-performance CdS LCLV to be realized, given the switching-ratio limitation of this device, as well as to allow the silicon LCLV, when completed, to fully benefit from this development. This program has resulted in the successful development of a silicon LCLV in which we have solved the edge breakdown effect, developed a novel Si/Si02 dielectric mirror, implemented a focusing-grid to improve resolution and scaled up the device from a 1 cm x 1 cm aperture to a 2 in. aperture device. This has resulted in a fast-response, high switching-ratio device approaching the resolution performance of the CdS light valve. The LC multimode operation has been successfully optimized, resulting in a practical demonstration...

: The development of a new type of large area infrared detector cell with visible light readout i... more : The development of a new type of large area infrared detector cell with visible light readout is studied in which a liquid crystal layer is electro-optically activated by a pyroelectric film. These studies include the evaluation of pyroelectric films and their poling techniques, the evaluation of liquid crystals for use with pyroelectric currents, analysis of thermal time constants in various cell layers, evaluation of signals obtained with test cells, and the development of prototype detectors. Polyvinylidene fluoride (PVF2) is selected as the best large area pyroelectric material available. In operation with 10.6 micrometer laser exposures, the effects of the pyroelectric generated voltage across the liquid crystal are obscured by thermal flow effects. However, a revised design is recommended in which a conductive faceplate is used to thermally isolate the pyroelectric film from the liquid crystal layer.

: During this contract, we accomplished the following major tasks toward the development of a CCD... more : During this contract, we accomplished the following major tasks toward the development of a CCD liquid-crystal light valve. We have demonstrated a fully operational CCD LCLV with a contrast ratio of 50:1 and a spatial resolution of 12 lines across the device. An alternative chip dicing method has been developed that reduces degradation to the substrate by a factor of 100. In addition, a new CCD LCLV packaging technique has been developed that improves the light valve fabrication yield from 30% to 80%. (Author)

L'invention porte sur un procede et sur un detecteur servant a determiner le rapport entre de... more L'invention porte sur un procede et sur un detecteur servant a determiner le rapport entre deux composants d'un melange fluide, comportant une cellule de controle en communication ouverte avec le melange, et une cellule de reference contenant un melange dans les proportions desirees et non en contact avec le melange a controler, les deux cellules presentant la meme geometrie. A l'aide d'un systeme diviseur de capacite, on determine les capacites relatives desdites cellules qui sont correlees avec les constantes dielectriques des differents melanges, et on determine le rapport entre un composant du melange et les autres composants du melange sur la base de correlations lineaires et monotones entre la constante dielectrique du melange a une temperature donnee et du rapport entre un composant du melange et les autres composants. Le melange a controler est de preference un melange de methanol et d'eau servant a alimenter un reformeur fournissant de l'hydrogene a ...

: The basic objective of this program has been to develop a silicon photoconductor liquid crystal... more : The basic objective of this program has been to develop a silicon photoconductor liquid crystal light valve (Si LCLV) for application in wide-field-of-view simulators. The Si LCLV is expected to offer several advantages over the cadmium sulfide (CdS) photoconductor LCLV, including higher sensitivity, a significantly better switching ratio, higher resolution, and (most importantly) a fast response time to allow higher 60-Hz operation. The main thrust of this program was to upgrade the device in the following areas: (1) Scale up to a 2-inch aperture device (from a 1 cm x 1 cm active area). (2) Implement the silicon/silicon dioxide (Si/SiO2) dielectric mirror and improve the light blocking layer. (3) Upgrade device resolution by optimizing the focusing grid. (4) Increase the contrast ratio by improving silicon processing. (5) Implement the dc-biased guard ring to prevent edge breakdown. (6) Optimize liquid crystal operation to reduce the reponse time. Significant improvements were ac...

Spatial Light Modulators and Applications I

ABSTRACT

The Review of Laser Engineering, 1982

Effective Utilization of Optics in Radar Systems, 1977

ABSTRACT

Conductive Polymers and Plastics, 1999

Publisher Summary This chapter discusses the development of conductive polymer-based transducers ... more Publisher Summary This chapter discusses the development of conductive polymer-based transducers for the detection of volatile organic compounds (VOCs) and other gaseous pollutants for application in environmental monitoring. In the experiment described in the chapter, highly sensitive sensor elements derived from polyaniline (PANI) are demonstrated for NO2 and other VOCs. A figure of merit is defined to allow the comparison of the response of different sensors to particular challenge vapors at various concentrations. The use of excess silane coupling agents to modify the surface of the sensor substrates in combination with excess of a sulfonic acid used to convert PANI to its conductive state results in highly sensitive, stable, and reversible VOC sensors, along with some polythiophene derivatives, for the detection of ketones, esters, and aromatic hydrocarbons. Individual sensors show different sensitivities to each class of VOC used in the study so that an array of these sensors generated a characteristic signature for each class demonstrating selectivity and classification.

Integrated Optics and Millimeter and Microwave Integrated Circuits, 1982

ABSTRACT

Optical Engineering, 1983

The structure, operation, and performance of the silicon-based liquid crystal light valves--the p... more The structure, operation, and performance of the silicon-based liquid crystal light valves--the photoactivated, CCD-addressed, and visible-to-IR converter--are described. The performance limitations of the readout structure, in particular those affecting resolution, sensitivity, contrast ratio, and speed, are discussed.

Journal of Power Sources, 2002

Exploratory studies on small plastic lithium-ion battery test cells with improved cathode materia... more Exploratory studies on small plastic lithium-ion battery test cells with improved cathode material show high pulse power capability and outstanding stability both in a 25°C pulse cycling test and in a 55°C calendar life test. Typical discharge pulse power values are 60mW/cm2. After 50,000 pulse cycles at 5C rates, cells at 25°C retain 100% of their initial 1C capacity and 75% of their pulse power capability. After 60 days at 55°C, cells measured at 25°C retain 98% of their initial 1C capacity and 70% of their pulse power capability. This performance is an excellent basis for the development of long life batteries for hybrid vehicles, as shown by a calculated scale up to a 30kW hybrid battery for a “Fast Response Engine”.

Journal of Applied Physics, 1975

ABSTRACT

Applied Physics Letters, 1984

A new method for the direct determination of minority‐carrier lifetime is presented, which utiliz... more A new method for the direct determination of minority‐carrier lifetime is presented, which utilizes transient capacitance measurements performed with varying depletion voltages on metal‐oxide‐semiconductor (MOS) structures. It is shown that the slope of the fill (storage) time versus the depletion voltage is directly proportional to the minority‐carrier lifetime. Good agreement is shown between results obtained with the proposed method and those obtained using a standard technique. The method is limited, however, to low‐doped MOS structures which can be depleted to the back contact.

Un relais optique (5) a deux diodes Schottky comporte un cristal liquide (80) permettant de modul... more Un relais optique (5) a deux diodes Schottky comporte un cristal liquide (80) permettant de moduler localement un faisceau (120) par rotation de la polarisation afin de produire un faisceau module (121), et un photo-conducteur (40) adjacent au cristal liquide (80) et permettant de recevoir et d'absorber un second faisceau (110). Le photo-conducteur (40) commande la polarisation par reaction au contenu optique du second faisceau (110). Le photo-conducteur (40) comprend un substrat a semi-conducteurs et une paire de diodes Schottky (60/40, 30/40) disposees sur les cotes opposes du substrat. L'absorption du second faisceau (110) par le substrat (40) produit des porteurs majoritaires generes par la lumiere. La paire de diodes Schottky (60/40, 30/40) assure l'appauvrissement substantiel du substrat en de tels porteurs et reflechit egalement le faisceau module a travers le cristal liquide.

Journal of Power Sources, 2002

Commercial supercapacitors, also known as ultracapacitors or electrochemical capacitors, from Saf... more Commercial supercapacitors, also known as ultracapacitors or electrochemical capacitors, from Saft, Maxwell, Panasonic, CCR, Ness, EPCOS, and Power Systems were tested under constant current and constant power discharges to assess their applicability for power-assist applications in hybrid electric vehicles (HEVs). Commercial lithium-ion batteries from Saft and Shin-Kobe were also tested under similar conditions. Internal resistances were measured by electrochemical impedance spectroscopy (EIS), as well as by the ''iR drop'' method. Self discharge measurements were also recorded. Compared with earlier generations of supercapacitors, the cells showed improved current and power capability. However, their energy densities are still too low to meet goals set by Partnership for a New Generation of Vehicles (PNGV) for HEV propulsion. Cells that use acetonitrile as the electrolyte solvent yield better performance, although safety issues need to be addressed. New high-power lithium-ion batteries show high energy densities, with high power capabilities.

Journal of applied …, 1985

The silicon liquid-crystal light valve U. Efron, J. Grinberg, PO Braatz, MJ Littfe, PG Reif, and ... more The silicon liquid-crystal light valve U. Efron, J. Grinberg, PO Braatz, MJ Littfe, PG Reif, and R. N. Schwartz Hughes Research Laboratories, Malibu, California 90265 (Received 30 July Î982; accepted for publication 6 My 1984) Detailed description is given of the structure, ...