A modified and improved polarizier ellipsometer allows for improved signal quality and signal to noise performance. This improvement is based on rotating one polarizer relative to the other fixed polarizer to generate AC mode signals related to a thin film under analysis. The AC mode signal may be compared to a background signal and the ratio of sample signal to background signal used to provide a more accurate assessment of film thickness. The normalized AC signal for an unknown thickness may be compared to a standard curve generated for a film of similar optical properties for an exact thickness determination or may be used directly to report a relative thickness value. Other modifications of the improved polarizer ellipsometer of the invention are also described where one or both of the fixed polarizers are removed to improve the signal intensity through reduction of the number of optical components. These modifications are designed to address specific thin film and substrate combinations.

This invention pertains to instruments of simple design and operation used to measure the thickness of thin films as a function of changes to or attenuation of incident light. The devices and methods of this invention are improvements of a fixed polarizer ellipsometer where film thickness can be related as a function of the degree of ellipticity in polarized light, or rotation of polarized light, that is reflected by a thin film. More specifically, the invention relates to improvements in ellipsometry that speed measurement acquisition time and reduce the cost of ellipsometry devices for use in specific binding assays and other applications. The invention also relates to instruments and methods where measurement of light attenuation by a thin film is no longer dependent on the generation of elliptically polarized light.
The following description of the background of the invention is provided simply as an aid in understanding the invention and is not admitted to describe or constitute prior art to the invention.
Optical measurements are commonly used to determine the thickness of thin films. Ellipsometers provide this information by determining the degree of ellipticity in polarized light that is reflected from a thin film. Ellipsometers typically include a light source, a polarizer, an analyzer, an optical compensator or quarter wave plate, and a detector. For example, U.S. Pat. No. 5,936,734 discloses using singly, partially, and/or multiply polarized electromagnetic radiation for ellipsometrically measuring regions of a patterened sample system, while U.S. Pat. No. 5,946,098 discloses a modified ellipsometer comprising a retarder element in the form of a prism.
Complex mathematical calculations are conventionally used to determine the film thickness. To use these mathematical calculations, the ellipsometer must have precise alignment of the rotating components for the measurement of signal intensity at the detector. Expensive and precise optical components must be used to provide for optimization of the detector signals in performing film thickness measurements. Measurement time is slow but the ellipsometer can provide precise thickness and refractive index determinations.
The rotation of ellipsometer components can be used to provide a sinusoidal plot of intensity at the detector as a function of time and angular velocity of the rotating component, as disclosed in U.S. Pat. No. 5,581,350. Measurements are made at two or more analyzer angles to determine the angle of the polarizer""s optical axis and the offset of the actual analyzer angle relative to its nominal angle. Measurements provide the angle of the analyzer""s optical axis and the offset of the polarizer angle relative to its nominal angle. This information is used to calibrate the ellipsometer, but the device operates according to time-consuming traditional principles that require precise alignment of rotating components for purposes of measuring film thicknesses. Similarly, U.S. Pat. No. 5,877,859 discloses rotating compensator ellipsometry methods, relying on a rotating compensator to produce a signal having a dc component, a two omega component, and a four omega component.
According to U.S. Pat. No. 3,985,447 it is also possible to rotate both the optical compensator and the polarizer at different angular speeds to measure the resultant transmitted optical intensity as a function of time. A Fourier analysis is used to determine the Stokes parameters of light that is reflected by the thin film. The film thickness and refractive index of the film can also be calculated in this manner based upon the Stokes parameters. A disadvantage of this device is that the system requires additional components including a time dependent rotating compensator. These additional components increase the expense and complexity of the system.
U.S. Pat. No. 4,725,145 discloses an instrument and method of use for measuring the state of polarization. The instrument contains only a photodetector. The photodetector has a partially specular surface and is placed at an oblique angle relative to the incident light source. The light adsorbed by the photodetector generates an electrical signal that is detected and related to the polarization of the light. The detector may be rotated to determine if the light contained any elliptical character. In the preferred mode of operation the entire system is rotated. The improvement is that the instrument does not include any wave retarders or polarizers. The system may contain one or more photodetectors. The amount of light adsorbed is a fraction of the incident radiation and is dependent on the incident light source and the azimuthal orientation of the plane of incidence. The detector surface rotates in a conical manner. Thus the plane of incidence is a plane which revolves around and through the incident light. The electrical output is modulated by the rotation and thus the modulation is a measure of the state of polarization of the light incident on the detector.
U.S. Pat. No. 5,552,889 discloses a method for measuring changes in polarized light that is independent of temperature. The method examines the AC and DC components of the light separately. The method requires an instrument design where two or more polarizers are arranged so that they are not orthogonal to each other. The modulation of the polarized signal is then measured at one or more photodetectors. The intensity of a constant component of the polarization signal is related to the position of the average plane of polarization. The alternating component of the polarization signal is normalized to the constant component and then the phase, amplitude, and position of the polarization is determined. The polarization signal is exactly linearized. The method requires a beam splitter to produce two beams of light.
U.S. Pat. No. 5,625,455 discloses an ellipsometer and an ellipsometric method. In the method the complex dielectric constant, the complex index of refraction, the transmittance, the reflectance, the adsorption coefficient, the optical density, and other optical properties may be measured by reflectance of a monochromatic light source. The instrument and method of use provide a direct measure of the optical and spectroscopic properties of the sample without numerical approximation or wavelength frequency scans. The light source should be elliptically polarized and the angle of incidence should be between 0xc2x0 and 90xc2x0. The digitized intensity data reflected or transmitted from the sample is analyzed using integrals or sums. The integrals eliminate noise and allow the method to start and stop at any analyzer angle.
In certain applications, it is possible to eliminate some of the components from an ellipsometer-like device for purposes of reducing the cost of manufacture while still providing an acceptable level of accuracy. U.S. Pat. No. 5,494,829 to Sandstrom et al. describes a device that operates according to the principles of ellipsometry, but has a fixed polarizer and a fixed analyzer with the additional cost advantage of having no optical compensator or other complex optical components. This device is used for binding assay analysis to determine whether a biochemical reaction has provided a thin film analyte indicating the presence of bacterial infection in a patient.
According to the ""829 patent, an antigen or an antibody is bound to a substrate and is incubated with an analyte solution that is prepared to include a body fluid specimen from a patient who is being tested for infection. A biochemical reaction grows a thin film on the substrate if the corresponding antibody or antigen is present in the solution. A positive test result is indicated by signal intensity at the detector relative to a delimiting threshold or background value. The device is typically calibrated to measure thickness in films having been produced by a particular antigenic reaction.
A number of spectrophotometric systems have been designed to analyze the thickness of films, in particular photoresist films. These instruments require complex arrangements of optical components or focus on specific geometric features in the film. The instruments may require detection of more than one wavelength or angle to determine the film thickness. Several of the methods will not work without exact information on the refractive index of the film. The spectrophotometers do not measure film thicknesses well on optical substrates with low reflectivity. The most significant limitation is the poor signal to noise ratio obtained with these instruments. These instruments also have difficulty measuring films such as amorphous silicon.
For example, U.S. Pat. No. 4,680,084 describes a very complicated instrument that uses multiple light sources and lens and beam splitters and more than one detector to determine the thickness of a film. In addition the method requires that the optical substrate have patterned features present that are opaque to the incident light. These features are used to correct the detected signal for contributions unrelated to the film thickness. U.S. Pat. No. 4,618,262 describes a laser-based interferometer that measures an etching process depth by the use of specific features on the optical substrate to determine when the etch process is complete. In this method the distance between adjacent maxima are used to determine the etching rate. The characteristic sinusoidal pattern terminates when the etch process reaches the optical substrate. This method must be able to resolve etch features on the order of 1-3 microns which is problematic because the laser beam is on the order of 700 microns in diameter. Thus resolution of these small features from background is difficult. Optical components have been added to the system to address this issue.
U.S. Pat. No. 5,494,829 describes the use of a simple calorimeter or reflectometer to measure a color change or a change in intensity for interpretation of binding assay results. The signal is a function of a change in wavelength or the change in intensity of a range of wavelengths where the optical substrate is designed to generate a visual interference effect and thus change color as a function of thickness change.
Each of the foregoing U.S. Patents describing the background of the invention is hereby incorporated by reference in its entirety, including all tables, figures, and claims.
There remains a need to provide inexpensive ellipsometric instruments that measure film thickness with acceptable accuracy for a variety of binding assays or other applications. This need may be addressed by ellipsometry, or other thin film mechanisms for light attenuation, where the device is capable of measurement without undue time being spent to align system components and without unnecessary optical components that reduce system efficiency. There also remains a need to provide inexpensive reflectometric instruments that measure film thickness with acceptable accuracy, without necessarily providing an absolute thickness determination, for a variety of binding assays and other applications according to the principles of multilayer film reflection theory. The reflectometric instruments should also be capable of performing measurements without undue time being spent to align system components, to acquire signals, or to analyze signals. The instruments of this invention are easy to operate and the data interpretation is straightforward. The instrument performance is highly predictable as the response to any particular binding assay system can be modeled and the instrumentation is tailored to analysis a particular binding assay surface construction or a range of similar constructions.
The invention provides devices and methods for use in measuring film thickness comprising an AC mode fixed polarizer ellipsometer. Use of the AC mode eliminates the need for the precise alignment of the polarizing elements, thus reducing the cost of manufacturing the device. In the AC mode, one of the polarization elements, e.g., the analyzer or the polarizer, is rotated in complete cycles at a constant speed in order to generate an alternating signal at the detector element. The device improves the signal over existing fixed angle polarizer ellipsometers because the change in signal versus the change in thickness produces a steeper slope (i.e., a larger signal difference for a change in thickness), and thus a better signal to noise ratio. As the analyzer or polarizer rotates, the signal received from a test surface varies with the rotation of the analyzer (polarizer), or varies as a function of time. The signal observed is thus a quasi-sinusoidal curve with an amplitude and phase that is characteristic of the film being analyzed. The data analysis can utilize any combination of features in the signal generated, but preferably uses a peak to peak difference as the output for a specific thin film. For instance, an average of all the peak signal strengths can be made and reported as the sample value. Exact thickness determinations can be made by comparison of the peak to peak value for an unknown sample relative to a standard curve of instrument output versus known film thicknesses. The standard curve is based on a film that is similar or identical in properties to the thin film to be analyzed and that is deposited on a substrate with the same structure as the substrate used with the test film. The standard curve can also be created by theoretical calculations. The AC mode ellipsometer is designed such that all instrument parameters are modeled to allow maximum thickness differentiation over a pre-determined range of thickness for a given optical support and thin film layer(s) combination.
Other instrument embodiments (reflectometric) involve the use of one polarizer or no polarizer, respectively, in the measurement of a change in the characteristics of light reflected from an optical substrate supporting one or more thin film. By eliminating one or both of the polarizers, the reflectometric instrument design is both less complex and less expensive. The removal of the polarizing elements also provides an advantageous increase in signal intensity, because any optical element will introduce some insertional loss of signal. The single polarizer instrument is preferably used when only one component (i.e., the s or p polarization component) of the incident light is to be used. In the single polarizer instrument either the polarizer or the analyzer may be removed.
Moreover, at a steep angle of incidence there is very little operational difference in the s- and p-components of light. Accordingly, if both components are used to measure film thickness, for example in a polarizer-free device, the instrument performs equivalently to a device comprising a polarization element. Thus, in other embodiments, the invention concerns polarizer-free devices which use unpolarized light at steep angles of incidence. The polarizer-free instrument is designed to analyze a specific optical substrate in order to measure a film created by the binding of a biological material, or a film created in other binding assays, over a range of film thicknesses. The thickness range to be accommodated depends on the type of binding assay to be performed. Based on empirical observation or theoretical calculations from thin film reflection theory, the proper wavelength of incident light and angle of incidence can be selected. Thus, a single instrument design can be selected that will accommodate a number of different binding assays based on a similar optical substrate.
In other preferred embodiments, the invention also provides methods of using any of the devices described herein to relate a change in light intensity to a change in film thickness. An exact thickness determination can be made by comparison to a standard intensity curve generated with known film thicknesses, where the standard curve is created with a known film that is optically similar to the test film. The detector signal intensity may be used without correction, or following correction using a comparative detector signal intensity (i.e., application of a normalizing function) obtained from a negative binding control sample, or other background measurement.
The present invention overcomes the problems known to those skilled in the art that are outlined above, and advances the art by providing cost-effective devices that measures film thickness with acceptable accuracy for a variety of binding assays and other applications according to the principles of ellipsometry. These advantages are obtained by rotating the analyzer or the polarizer to produce a quasi-sinusoidal intensity in reflected light from the sample under test and by mapping selected intensity values to a film thickness through the use of a standard curve or other reference data. This concept permits the devices described herein to perform film thickness measurements without undue time being spent to align system components and without the use of complex mathematics and optical components. The system is inexpensive to manufacture because it does not require the use of an optical compensator, quarter wave plate, or other precision optical components and component alignment.
Thus, in a first aspect, the invention describes devices for use in determining a film thickness of a sample. The devices can comprise a substrate for supporting the sample; a light source for producing electromagnetic radiation to illuminate the sample; a first polarization element located between the light source and the sample; a detector for detecting electromagnetic radiation reflected from the sample; and a second polarization element located between the detector and the sample. At least one of the first and second polarization elements can be rotated to vary an s and/or p content of the electromagnetic radiation with time. The signal obtained from the detector is used to determine film thickness by a method comprising the use of a standard function that correlates film thickness to detector signal intensity.
In particularly preferred embodiments, one or more of the following can be included in the devices: (i) a light source that produces monochromatic electromagnetic radiation, (ii) electromagnetic radiation selected from the group comprising visible light, infrared light, and ultraviolet light, (iii) a first polarization element comprising a rotatable polarizing filter, (iv) a second polarization element comprising a rotatable polarizing filter, (v) a first polarization element comprising a rotatable polarizing filter, and a second polarization element comprising a fixed analyzer, (vi) a first polarization element comprising a fixed polarizing filter, and a second polarization element comprising a rotatable analyzer, (vii) rotating at least one of the first and second polarization elements to provide a quasi-sinusoidal intensity signal at said detector, (viii) relating a film thickness to an amplitude of the quasi-sinusoidal intensity signal, (ix) relating a film thickness to a peak to peak amplitude of the quasi-sinusoidal intensity signal, (x) a control sample comprising a known film thickness, (xi) a control sample that is a negative control sample, (xii) a standard function comprising a normalizing function which relates the detector signal intensity to a comparative detector signal intensity obtained from the negative control sample, and (xiii) a normalizing function that is a ratio of the detector signal intensity and a comparative detector signal intensity obtained from the negative control sample.
The term xe2x80x9csamplexe2x80x9d as used herein refers to any material which can be deposited on the surface of a substrate to form a film. Preferred samples can be organic materials such as biological materials (e.g., nucleic acids, antibodies, antigens, receptors, analytes, chelators, enzyme substrates, etc.), or inorganic materials such as silicon oxide, silicon dioxide, silicon nitride, etc. A sample preferably can be a solution containing such materials. The term xe2x80x9cnegative control samplexe2x80x9d as used herein refers to any substrate which lacks a thin film. Such a negative control sample can be used to provide a baseline or comparative signal from the device.
The terms xe2x80x9cfilmxe2x80x9d and xe2x80x9cthin filmxe2x80x9d as used herein refer to a one or more layers of sample material deposited on a substrate surface. A film can be about 1 xc3x85 in thickness, about 5 xc3x85 in thickness, about 10 xc3x85 in thickness, about 25 xc3x85 in thickness, about 50 xc3x85 in thickness, about 100 xc3x85 in thickness, about 200 xc3x85 in thickness, about 350 xc3x85 in thickness, about 500 xc3x85 in thickness, about 750 xc3x85 in thickness, about 1000 xc3x85 in thickness, and about 2000 xc3x85 in thickness. Particularly preferred are films from about 5 xc3x85 to about 1000 xc3x85; most preferred are films from about 5 xc3x85 to about 350 xc3x85.
The terms xe2x80x9csubstrate,xe2x80x9d xe2x80x9coptical supportxe2x80x9d and xe2x80x9csupportxe2x80x9d as used herein refer to a support within a device for a sample under study. Suitable substrates can be made of any reflective material known by those skilled in the art, and provide a planar surface upon which a sample film is deposited. Preferably, the substrate is a polished silicon wafer, alumina, or glass or a material coated with one or more of these materials. For example, a substrate may be a polycarbonate membrane coated with a layer of amorphous silicon, a fibrous material coated with aluminum or chromium and an optical layer of amorphous silicon, or a ceramic coated with a layer of metal and/or amorphous silicon. The primary consideration for selection of the substrate is the reflectivity of the material and/or its ability to be coated with a reflective material.
The term xe2x80x9coptical pathwayxe2x80x9d as used herein refers to a pathway within a device through which electromagnetic radiation may pass. The optical pathway serves to direct electromagnetic radiation from a light source to a sample under study, and ultimately to a detector that measures one or more properties (e.g. intensity, polarization, etc.) of light that is reflected by the sample. The optical pathway may contain various elements of the device, such as polarization elements that are positioned to polarize incoming electromagnetic radiation from the light source prior to contact with the sample under study, and/or electromagnetic radiation reflected from the sample under study. The optical pathway preferably includes only those components that are required to permit the detector to provide signals that facilitate qualitative measurements of film thickness. Such devices can be cost-effectively deployed for applications where ellipsometers have not been traditionally used, for example, in the physician""s office.
The term xe2x80x9clight sourcexe2x80x9d as used herein refers to any source of electromagnetic radiation. Electromagnetic radiation can also be referred to as xe2x80x9clight.xe2x80x9d Such electromagnetic radiation may include wavelengths from about 10xe2x88x926 xcexcm to about 108 xcexcm, preferred is electromagnetic radiation from the ultraviolet to infrared wavelengths; particularly preferred electromagnetic radiation is visible light. Suitable light sources are well known to those skilled in the art, and can include any source of monochromatic or polychromatic radiation. The use of monochromatic radiation is preferred. The terms xe2x80x9cmonochromatic radiationxe2x80x9d or xe2x80x9cmonochromaticxe2x80x9d light as used herein refer to electromagnetic radiation having a bandwidth that is sufficiently narrow to function as a single wavelength for design purposes. Preferred light sources are lasers, laser diodes, and light emitting diodes.
As used herein, the term xe2x80x9cdetectorxe2x80x9d refers to any device for detecting electromagnetic radiation by the production of electrical or optical signals, and includes photomultipliers, photodiodes, and photochemical reagents, whether these detectors are driven to provide analog or digital signals, as well as any other light detection device. Preferred detectors detect electromagnetic radiation, particularly visible light, with the resulting production of electrical or optical signals. A signal processing element can process these signals to yield this information, for example by the use of standard curves, to associate the signals with a film thickness. In especially preferred embodiments, the film thickness is interpreted as a binding assay result, e.g., the result of a test showing either a positive, negative, or inconclusive result in a test for a specific analyte.
The term xe2x80x9cpolarization elementxe2x80x9d as used herein refers to a device that receives incoming electromagnetic radiation, and produces therefrom radiation which is polarized. Suitable polarization elements, such as polarizing filters and analyzers, are well known to those skilled in the art. As described herein, polarization elements can be positioned to polarize incoming light from the light source prior to contact with the sample under study, as well as light reflected from the sample under study. A polarization element can be fixed within the optical pathway. Alternatively, one or more of the polarization elements can include a mechanism for varying s- and p-components of polarized light with time by rotating the polarization element, or a component thereof, on its optical axis. Preferably, this mechanism rotates a polarizing filter that is located in the position of a polarizer or analyzer in a conventional ellipsometer. Rotation of a polarizing filter provides a corresponding quasi-sinusoidal intensity in the electromagnetic radiation that is reflected from the sample under study.
The term xe2x80x9clinear polarizationxe2x80x9d as used herein refers to a polarization state that is essentially all s-polarization or all p-polarization. Electromagnetic radiation is linearly polarized if, in either linear state, there is not enough of the other polarization state to affect the outcome of the measurement. Preferably, a linear polarizing filter may be rotated up to about 20xc2x0 rotation off of its optical axis without introducing appreciable measurement errors; more preferably, this rotation is limited to less than about 10xc2x0; even more preferably, limited this rotation is limited to less than about 5xc2x0, with a precise alignment of about 1xc2x0 or less being most preferred.
In another aspect, the invention concerns methods of measuring a film thickness of a sample. The methods can comprise providing a device comprising a light source, a polarizer, an analyzer, and a detector; directing electromagnetic radiation from the light source towards the sample, whereby electromagnetic radiation is reflected from the sample; polarizing the electromagnetic radiation that is directed towards the sample using the polarizer; polarizing the electromagnetic radiation reflected from the sample using the analyzer; rotating the polarizer or the analyzer to vary the s and p content of the polarized electromagnetic radiation with time; detecting the polarized electromagnetic radiation reflected from the sample using the detector to obtain a signal corresponding to the intensity of the reflected electromagnetic radiation; and correlating the signal to the film thickness of the sample using a standard function that relates film thickness to detector signal intensity. Other data analysis means can be used as known to those skilled in the art.
In particularly preferred embodiments, one or more of the following may be included in the methods: (i) a standard function selected from a plurality of standard functions obtained from samples having different optical properties, (ii) a comparative detector signal intensity obtained from a negative control sample, (iii) a standard function comprising a normalizing function which relates the detector signal intensity to the comparative detector signal intensity, (iv) a normalizing function that is a ratio of the detector signal intensity and the comparative detector signal intensity, and (v) a polarizer or an analyzer that provides a corresponding quasi-sinusoidal signal from the detector.
Selected signals can be obtained in a time domain corresponding to predetermined degrees of rotation of the polarizing filter, or other polarization element, which varies the s and p content of the polarized light. These intensity signals are used as input to generate a standard function, e.g., standard curves of empirical or theoretical data that relate film thickness as a function of the magnitude of detector signal intensity through a range of polarizing rotation. Any mapping technique may be used to relate or map the intensity corresponding to a particular degree of rotation with a film thickness. These other mapping techniques may include, without limitation, neural networks and adaptive filters, which are all referred to in the context of this application as xe2x80x9cstandard functionsxe2x80x9d.
A particular advantage that derives from the ellipsometric embodiments of the invention is that operation of the device does not require time consuming positional adjustment of the polarization element in order to optimize intensity in signals from the detector. More particularly, measurement data can be collected from all points in the cycle of polarizing rotation and used to establish a peak to peak amplitude of the quasi-sinusoidal signal. This peak to peak amplitude is used as input into the standard curve in order to determine film thickness.
A particularly preferred feature of the ellipsometric embodiments is the use of a normalizing function that expresses the detector signal intensity in relationship to a comparative detector signal intensity obtained from a negative control sample. This normalizing function is most preferably a ratio between the detector signal intensity and the comparative signal intensity from the negative control sample, e.g., the detector signal intensity divided by the intensity of the signal from the negative control sample.
In another aspect, the invention concerns devices for use in interpreting thin film binding assays which comprise a substrate for supporting a sample; a light source for producing electromagnetic radiation to illuminate the sample; a detector for detecting electromagnetic radiation reflected from the sample; an optical pathway between the light source, the sample, and the detector; and a signal processor for correlating the signal with a film thickness on the sample. The optical pathway comprises a fixed polarization element located between the sample and the detector to linearly polarize the reflected electromagnetic radiation. A signal produced by the detector corresponds to the intensity of the electromagnetic radiation reflected from the sample.
In particularly preferred embodiments, one or more of the following can be include d in the device: (i) a light source that produces monochromatic electromagnetic radiation, (ii) electromagnetic radiation preferably selected from the group comprising visible light, infrared light, and ultraviolet light, (iii) linearly polarized electromagnetic radiation that is essentially s- or p-polarized relative to a plane of incidence in the optical pathway between the polarizer and the detector, (iv) relating a film thickness to a thin film binding assay result, and (v) an optical pathway comprising a single polarization element.
In another aspect, the invention concerns methods of measuring a film thickness of a sample which comprise providing a device comprising a light source, a detector, a first optical pathway between the light source and a sample, and a second optical pathway between the sample and the detector; directing electromagnetic radiation from the light source along the first optical pathway to the sample, such that electromagnetic radiation is reflected by the sample along the second optical pathway to the detector; linearly polarizing the electromagnetic radiation along the first optical pathway at a position prior to contact of the electromagnetic radiation with the sample; detecting the electromagnetic radiation reflected by the sample using the detector to obtain a signal corresponding to the intensity of the reflected electromagnetic radiation; and correlating the signal to the film thickness of the sample.
In particularly preferred embodiments, one or more of the following can be included in the methods: (i) linearly polarized electromagnetic radiation that is essentially s- or p-polarized relative to a plane of incidence in the second optical pathway between the polarizer and the detector, (ii) relating a film thickness to a thin film binding assay result, and (iii) performing the method without polarization of the electromagnetic radiation reflected from the sample.
In another aspect, the invention concerns methods of measuring a film thickness of a sample which comprises providing a device comprising a light source, a detector, a first optical pathway between the light source and a sample, and a second optical pathway between the sample and the detector; directing electromagnetic radiation from the light source along the first optical pathway to the sample such that electromagnetic radiation is reflected by the sample along the second optical pathway to the detector; linearly polarizing the electromagnetic radiation along the second optical pathway at a position after contact of the electromagnetic radiation the said sample; detecting the electromagnetic radiation reflected by the sample using the detector to obtain a signal corresponding to the intensity of the reflected electromagnetic radiation; and correlating the signal to the film thickness of the sample.
In particularly preferred embodiments, one or more of the following can be included in the methods: (i) linearly polarized electromagnetic radiation that is essentially s-or p-polarized relative to a plane of incidence in the second optical pathway between the polarizer and the detector, (ii) relating a film thickness to a thin film binding assay result, and (iii) performing the method without polarization of the electromagnetic radiation prior to reflection from the sample.
An optical pathway according to the invention includes specific combinations of elements that operate according to the principles of multiple thin-film reflection theory. In a preferred embodiment, the optical pathway comprises a polarizing filter that is positioned to linearly polarize light prior to its illumination of the sample under study. In other preferred embodiments, the optical pathway comprises a polarizing filter that is positioned to linearly polarize light that is reflected from the sample under study.
In these two instrument configurations, the polarization element, either in the path of the incident electromagnetic radiation or in the path of reflected electromagnetic radiation, is used to select one component of the polarized electromagnetic radiation, i.e., either the s- or the p-component. When the polarizing element is in the path of the incident electromagnetic radiation, the s- or p-polarized electromagnetic radiation is incident on the sample under study. Upon interaction with the sample under study, the electromagnetic radiation undergoes an amplitude change relative to electromagnetic radiation that has reflected from a sample under study without the added thin film, e.g. relative to a negative control sample. The reflected electromagnetic radiation is not elliptically polarized, and there is no change in the degree of polarization. Rather, there is only an attenuation of the light relative to the light that is reflected from a sample that does not have an added thin film. A similar case is generated when the incident electromagnetic radiation, and thus the reflected electromagnetic radiation, is unpolarized. In such a case, a polarization element in the path of the reflected electromagnetic radiation will pass only one component of the electromagnetic radiation to the detector.
In another aspect, the invention concerns devices for use in interpreting thin film binding assays which comprises a substrate for supporting a sample, a light source for producing electromagnetic radiation to illuminate the sample, a detector for detecting electromagnetic radiation reflected from the sample, an optical pathway between the light source, the sample, and the detector, and a signal processor for correlating said signal with a film thickness on said sample. A signal produced by the detector corresponds to the intensity of electromagnetic radiation reflected from the sample.
In particularly preferred embodiments, one or more of the following can be included in the devices: (i) a light source that produces monochromatic electromagnetic radiation, (ii) electromagnetic radiation selected from the group comprising visible light, infrared light, and ultraviolet light, (iii) a light source positioned relative to the sample and the detector to provide a low angle of incidence, (iv) an optical pathway comprising neither a polarizer located between the light source and the sample, nor a polarizer located between the sample and the detector, (v) a light source positioned at an angle of incidence ranging from about 0xc2x0 to about 30xc2x0, determined relative to a line normal to the plane of the sample, (vi) a light source positioned at an angle of incidence ranging from 0xc2x0 to 20xc2x0, (vii) a light source positioned at an angle of incidence ranging from 0xc2x0 to 10xc2x0, (viii) relating a film thickness to a thin film binding assay result, (ix) an optical pathway comprising a polarizing filter which provides circularly polarized light, (x) a polarizing filter located in the optical pathway between the light source and the sample, and (xi) a polarizing filter located in the optical pathway between the sample and the detector.
In another aspect, the invention describes a method of measuring a film thickness of a sample which comprises providing a device comprising a light source, a detector, a first optical pathway between the light source and a sample, and a second optical pathway between the sample and the detector; directing electromagnetic radiation from the light source along the first optical pathway to the sample such that electromagnetic radiation is reflected by the sample along the second optical pathway to the detector; detecting the electromagnetic radiation reflected by the sample using the detector to obtain a signal corresponding to the intensity of the reflected electromagnetic radiation; and correlating the signal to the film thickness of the sample. Preferably, the electromagnetic radiation is unpolarized at said detector without movement of components in said optical pathway.
In particularly preferred embodiments, one or more of the following can be included in the method: (i) a light source positioned at a low angle of incidence determined relative to a line normal to the sample, (ii) an optical pathway comprising neither a polarizer located between the light source and the sample, nor a polarizer located between the sample and the detector, (iii) a low angle of incidence ranging from about 0xc2x0 to about 30xc2x0, (iv) a low angle of incidence ranging from 0xc2x0 to 20xc2x0, (v) a low angle of incidence ranging from 0xc2x0 to 10xc2x0, and (vi) relating a film thickness to a thin film binding assay result.
In these preferred embodiments, the invention describes devices in which the light source and the detector are positioned in the device at angles of incidence where essentially unpolarized reflected light to the detector can be used. In this device configuration, the light source can be positioned at an angle of incidence ranging from about 0xc2x0 to about 30xc2x0, determined relative to a line normal to the plane of the sample. Preferably, the angle of incidence can be about 0xc2x0, about 5xc2x0, about 10xc2x0, about 15xc2x0, about 20xc2x0, about 25xc2x0, or about 30xc2x0. The wavelength of the electromagnetic radiation to be provided can be determined empirically, using multilayer thin film reflection theory that is well known in the art. Using such theory, the selected wavelength is a function of the angle of incidence, the approximate thickness of the thin film on the sample under study, and the reflective surface that is used to support the thin film.
In any of the reflectometric embodiments, it is preferred to have no additional polarizing means other than those that are specifically mentioned. For example, in the first reflectometric embodiment where light is polarized prior to contact with the sample under study, it is preferred not to have a polarizing filter located between the sample and the detector. Similarly, in the second reflectometric embodiment where light is polarized after contact with the sample under study, it is preferred not to have a polarizing filter located between the sample and the light source. In the third reflectometric embodiment, it is preferred not to have any polarizing filters.
The most cost effective devices described in the invention simply mount a light source on a housing or frame that positions the light source relative to the substrate and the detector in a manner providing a suitable angle of incidence. Reflected light from the substrate arrives at the detector relative to the incident light or light that is reflected from the surface without a thin film. In this case, the light source is a monochromatic light source and the combination of elements includes neither a polarizer located between the light source and the sample under study nor an analyzer located between the sample under study and the detector.
A particular advantage of the present invention is that operation of the reflectometric embodiments do not require positional adjustment of the polarization elements. Removing one or more of the polarizing elements from the instrument""s optical path increases the amount of light available to the detector. Thus, the instrument is more sensitive than conventional instruments, where light is lost by passage through the polarizing elements. More particularly, measurement data is collected as a detector signal intensity that is compared to a delimiting value. This delimiting value is associated with a background or negative test result or other indicator of film thickness change. In its most fundamental form, the interpretation of test results is essentially an answer of yes or no, positive or negative, based upon signal intensity measurements showing the presence or absence of a thin film or the presence of a film with a thickness greater than a preselected threshold thickness. In such a preferred embodiment, actual film thickness does not need to be calculated, provided the test results conclusively establish the presence or absence of such a film. Because the signal is a function of the film thickness, and the film thickness is a function of analyte concentration in a sample, the instrument can also provide a quantitative determination of analyte concentration without an absolute determination of the film thickness.
It is also contemplated that the test interpretation could include a third indicator, namely, an indicator that the test is inconclusive because the signal intensity falls within a range of values between a definite negative and a definite positive.
In addition to assays where direct detection of analyte binding results in an increase in thickness on the thin film support, assays where a decrease in thickness or where the analyte concentration is inversely related to signal can be envisioned. Examples of such assays would include enzymatic degradation of the thin film surface where the substrate is specific to an enzyme as the analyte of interest or a competitive assay where the analyte competes with the amplifying reagent and the thickness change decreases with increasing analyte concentration.
Also instrument response to a change in thickness can be an increase in light intensity to the detector or a decrease in light intensity to the detector.

Instruments for analyzing binding assays based on attenuation of light by thin films


ABIST apparatus with integrated directory compare logic functionality, and ABIST error detection functionality. The apparatus includes two subsystems NOR'ed together. The first subsystem is for bit-wise logically ANDing corresponding array valid bits and tag valid inputs, generating “0” for a match and “1” for a mis-match, and logically ORing the bit-wise result to generate a “1” hit if there are any bit-wise mismatches. The second subsystem further receives ABIST control logic as an input to either: (a). combine array valid bits tag valid inputs to produce valid output, or (b) compare array valid bits with tag valid inputs. The apparatus further includes logical NOR functionality for the outputs of the first and second subsystems.

In order to test RAM macros, e.g., SRAM directory macros, by means of Array Built In Self Test (ABIST), the data from the array is usually compared to expected data. To accomplish this, the ABIST requires additional circuitry. This additional circuitry is either embedded in the SRAM or provided in surrounding logic.
Directory macro's are microprocessor cache components that are used to determine if a particular address is currently held in the main cache RAM. Typically, a directory RAM holds a portion of the addresses stored in the main cache RAM. A portion of the full address is used to retrieve and latch an entry from the RAM. Another portion of the address ("tag") is then compared against the latched entry from the RAM. If the tag matches the entry retrieved from the RAM, the cache is said to have found a "hit".
Typically, the logic to accomplish this utilizes RAM output to generate a "hit" signal. A set of bits from the RAM are compared bit by bit with the corresponding tag bits using an XOR gate. The output of any XOR is a "1" if the corresponding RAM bit and tag bit are mismatched, that is, the tag bit and the RAM bit are not equal to each other. If, however, none of the XOR gates generate a mismatch, that is, all of the RAM bits are equal to the corresponding tag bits, then the output of a second stage NOR gate will be a "1", meaning that the cache found a hit. The speed at which the cache can operate is directly affected by how long it takes for this compare structure to evaluate the inputs. This, in turn, depends upon the length of the logic path.
A clear need exists to reduce the length and complexity of the logic path, and thereby reduce the time required for the cache to operate.
There is also a clear need to reduce the circuit overhead of the directory compare and logic function and the ABIST error detection function.

Integrated system logic and ABIST data compression for an SRAM directory

International Business Machines Corporation


A device (10) for fixing a pulley (40) includes a rotating pin (12) on the outer surface of which the pulley (40) may be fixed. The rotating pin (12) has at least one locking element (50) movable between a first locking position where it retains the pulley (40) and a second releasing position where it does not retain it. The locking element (50) is coupled with at least one element (60) which can be operated by the user so that the displacement of said at least one element (60) which can be operated by the user causes the displacement of the at least one locking element (50) between the first and second position.

1. Field of the Invention
In very many applications it is required to employ pulleys in order to transmit a rotating movement, raise loads, vary the direction of a cable, etc.
2. Description of the Related Art
Normally the pulleys (or generally a rotating wheel) are fixed to the pin on which they rotate either permanently or otherwise via fixing means which range from split pins to bolt-type fastening systems. Not infrequently the pulley must be removed from the pin by means of a very quick and simple operation, for example so as to replace it with a different pulley.
An example of this arises in the sector of tubular gearmotors to which reference will now be made by way of example.
Tubular gearmotors for moving and/or automating roller blinds, such as shutters, blinds and curtains, at present are designed in such a way that they may be inserted inside a winding drum on which the said shutter is wound (and unwound). They comprise principally an electric motor, a speed reducer and a capacitor, which are housed inside a tubular body. Two pulleys for transmission of the rotating movement from the gearmotor to the winding drum are provided at the ends of the metallic tubular body.
The transmission pulleys have a grooved external profile which matches the internal form of the winding drum. The first pulley is mounted on an output pin of the gearmotor, while the second pulley is mounted on the end-of-travel mechanism. The invention relates to the first pulley.
Usually this pulley is fixed to the rotating pin either with permanent fixing means (screws, washers, etc.) or by means of a tongue arranged on the rotating pin. The tongue engages inside a corresponding seat of the pulley once the latter has been inserted on the pinion. The pulley also has, formed in it, a groove inside which a screwdriver can be inserted in order to lower the tongue and extract the pulley from the pinion.
This solution has the disadvantage that the pulley replacement operation requires precisely the insertion of a screwdriver, for which the installation operator must use one hand, while with the other hand the pulley must be removed.
If one considers that very often replacement is performed once the gearmotor has been installed and therefore in a position which is not easily accessible (for example inside the recess of a wall reached by means of a ladder), it is easy to appreciate the awkward nature of this operation and the danger of not being able to hold on with at least one hand.


There is provided an embossed particleboard, which can be used, for example, as a siding. The particleboard comprises a monolayer embossed particleboard including wood particles having an average size of less than 4 mm, a resin, and optionally a sizing agent. There is also provided a method of manufacturing a wood-based product such as a siding. The method comprises embossing and pressing in a single step a monolayer mat comprising wood particles having an average size of less than 4 mm and a resin, so as to obtain an embossed monolayer particleboard siding.

Siding such as exterior siding of a building can be made of various materials. Many siding products encountered on the market are wood-based products. Such wood-based products include High Density Fiberboard (HDF) siding, Medium Density Fiberboard (MDF) siding, hardboard siding (Canaxel™) and Oriented Strand Board (OSB) siding. In order to provide these products with an interesting look such as a look that imitates natural wood, some manufacturers decided to emboss the siding so as to provide a wood grain embossing pattern to the siding.
However, the technologies that are available in order to prepare such products comprise important drawbacks. In a general manner, such products are prepared by using processes that comprise several steps and that are quite complicated. This also explains the relatively high price of the embossed siding.
Embossed MDF or HDF siding has interesting mechanical properties and it can be easily machined but its production costs are quite high since fibers must be refined.
It would thus be desirable to be provided with an alternative to the existing siding.

Embossed monolayer particleboards and methods of preparation thereof


A flexible platform jointed to a conveyor belt for a combined harvesting, chopping and spinning machine includes a central assembly of parallel augers and an oblique auger on each side of the assembly.

In regards to the previous art of the present invention, it is worth highlighting platforms with transporting augers and conveyor belt platforms or canvas, as they were named in the past, which were rigid or without movement, except from its own turn, in all its length and without the possibility of copying the land in which they worked. This aforementioned canvas consisted of a conveyor belt on each side of the feeder and a central vertical belt.
It is worth mentioning that for some cereal harvesting or products, the aforementioned conveyor belts have to be flexible, that is to say, they must allow the belt to take such an angle that it must copy the land and said form to adapt to land irregularities, being one of the main objectives of the present invention to develop a cutting platform which fulfills the demands of farming in lands with irregularities.
The proposed platform in a preferential embodiment is built with high technology materials and low weight materials such as steel, plastic and aluminum or such material's alloys.
The present platform is developed with several conveyor belts, located parallel to one another on each lateral side of said platform, back belts being rigid or without movement (except for the belt's own turn) regardless of the land where it works; existing
front conveyor belts, which bend or joint in relation to the back conveyor belts, allowing to change its position and accepting land irregularities.
In a preferential embodiment, the proposed platform allows turn revolutions or belt velocity to be the same or different in back conveyor belts in relation to the belts' velocity of the front belts, likewise allowing it to be of a different width, length or material and to have different shapes.
Other important aspect is that both conveyor belts are split through its width into multiple pieces letting belts to have several clearance spacing, which brings the multiple point self-cleaning characteristic to conveyor floor.
The back conveyor belt and the front conveyor belt will carry the cereal, grain or material towards the central conveying system, that comprises of a set of synchronized augers, where it is first taken by the oblique side augers and then moved to the combine feeder by the horizontal augers.
Likewise, the cutting system is also synchronized to eliminate cutting-blade vibration, for that reason it was built with a gear-box and a control gear, in order not to be slipped or moved in both sides.
The conveyor belts can be activated mechanically or hydraulically, with any of the mechanisms known today to give movement to these types of belts.
By being the flexible front conveyor belt, it can vary its angle in relation to the back conveyor belt, having up to 200 mm trajectory.

Flexible platform joined to a conveyor belt for a combine harvester


A method implemented by a processor of a computing device, comprising: receiving an image from a camera; using a machine vision process to recognize the at least one real-world object in the image; displaying on a screen an augmented reality (AR) scene containing the at least one real-world object and a virtual agent; receiving user input; deriving a simplified user intent from the user input; and in response to the user input, animating the virtual agent within the AR scene, the animating being dependent on the simplified user intent. Deriving a simplified user intent from the user input may include converting the user input into a user phrase, determining at least one semantic element in the user phrase, and converting the at least one semantic element into the simplified user intent.

Augmented reality has transformed the world of computer games, allowing the mixing of real-world images with depictions of virtual objects. However, while such games may allow the detection of surfaces (AR planes) from real-world images, they remain limited insofar as the user's ability to communicate with virtual agents is concerned. This leads to games that are less exciting to play and less likely to be purchased by consumers.

Communication with augmented reality virtual agents


Disclosed is a thermoplastic resin composition comprising A) 100 parts by weight of a basic resin comprising 11 to 89% by weight of an acrylonitrile-butadiene-styrene copolymer and 89 to 11% by weight of a styrene-acrylonitrile copolymer, B) 10 to 40 parts by weight of a bromine organic flame retardant, and C) 0.1 to 10 parts by weight of a coated antimony compound.

1. Field of the Invention
The present invention relates to a thermoplastic resin composition with superior flame retardancy, colorability and scratch resistance. More particularly, the present invention relates to a thermoplastic resin composition which exhibits flame retardancy, impact strength, scratch resistance, colorability and surface hardness based on a synergistic effect through incorporation of a bromine organic flame retardant and a coated antimony compound in a resin containing an acrylonitrile-butadiene-styrene copolymer.
2. Description of the Related Art
In general, an acrylonitrile-butadiene-styrene (hereinafter, referred to as ABS) resin is widely used as exterior materials of electric/electrical products and office machines and the like due to stiffness and chemical resistance of acrylonitrile, and processability and mechanical strength of butadiene and styrene. However, the ABS resin is inherently combustible and is vulnerable to fire.
Due to these problems, the ABS resin used for electric/electrical products, office machines and the like should satisfy flame-retardancy standards in order to secure safety against flames. Methods for imparting flame retardancy to ABS resins include polymerization of rubber-modified styrene resins through incorporation of flame retardant monomers, mixing a flame retardant and a flame retardant aid with the prepared rubber-modified styrene resin and the like.
The flame retardants may be classified into halogen flame retardants and non-halogen flame retardants. The non-halogen flame retardants should be added at a relatively greater amount due to considerably low flame retardancy efficiency, as compared to halogen flame retardants, thus causing deterioration in mechanical and physical properties of rubber-modified styrene-based resins.
Accordingly, the most general method for imparting flame retardancy to an ABS resin is to use a halogen flame retardant. The halogen flame retardant is effective in improving flame retardancy, while maintaining mechanical and physical properties of a rubber-modified styrene resin. In particular, a bromine flame retardant is particularly effective. However, the ABS resin to which flame retardancy is imparted has considerably low scratch resistance due to inherent butadiene rubber characteristics of the ABS resin and ABS resin products with high gloss are disadvantageously readily scratched.
Meanwhile, a flame retardant aid does not exhibit complete flame resistance, but has improved flame resistance effects, when used in conjunction with a flame retardant, thus advantageously reducing a content of the flame retardant. Generally, in a case in which a halogen flame retardant is used, use of an antimony compound as a flame retardant aid is particularly effective.
However, when a flame retardant ABS resin is prepared from a conventional antimony trioxide compound, problems such as deterioration in physical properties, for example, impact strength and colorability of the resin occur. The antimony trioxide compound also has regulatory issues such as prohibition or restriction of use thereof due to risk and negative effects on the human body and environment. In addition, most flame retardant ABS resins have a scratch resistance, measured as pencil hardness, of 3B or 4B.
Accordingly, there is increasing demand for development of ABS resins which maintain superior scratch resistance, impact strength and flowability, and exhibit superior flame retardancy.

Thermoplastic resin composition having excellent flame retardancy, coloring properties and scratch resistance


The present invention is directed to microwaveable grilled cheese and grilled cheese and meat sandwiches that include an edible, lipid based moisture barrier. The edible moisture barrier includes an edible microparticulated high melting lipid and an edible low melting triglyceride blend.

For many food products, especially prepackaged sandwiches, moisture levels must be maintained if the product is to exhibit optimum organoleptic properties, quality, and taste. Moisture migration in finished food products can seriously compromise quality, stability, and organoleptic properties. In addition, many chemical and enzymatic deteriorative reactions proceed at rates partially governed by the moisture content of foods. Excessive rates of these reactions can promote deleterious changes in the flavor, color, texture, and nutritive value of food products.
In multi-component food products, particularly those having components with different moisture contents and water activities such as prepackaged grilled cheese sandwiches, moisture can migrate between adjacent components, altering the component's characteristics and organoleptic properties. In addition to compromising the quality of finished food products, moisture migration can hinder production and distribution of food products. Thus, for example, the cheese in the sandwich may dry out while, at the same time, the texture of the bread may change with time, especially becoming soft and/or soggy.
One method to prevent moisture migration in foods involves coating one or more surfaces of the food product with an edible moisture barrier. Such barriers should have a low moisture permeability in order to prevent the migration of water between areas of differing water activities. In addition, the barrier should cover the food surface completely, including crevices, and adhere well to the food product surface. The moisture barrier should be sufficiently strong, soft, and flexible to form a continuous surface that will not crack upon handling, yet can be easily penetrated during consumption. In addition, the barrier film's organoleptic properties of taste, aftertaste, and mouthfeel should be imperceptible so that the consumer is not aware of the barrier when the food product is consumed. Finally, the moisture barrier should be easy to manufacture and easy to use.
Because lipids, such as oils, fats, and waxes, are composed of lipophilic water insoluble molecules capable of forming a water impervious structure, they have been investigated for use in moisture barrier films. With respect to oleaginous materials derived from lipids (i.e., sucrose polyesters, acetylated monoglycerides and the like) and/or other film forming lipids, it has been shown that, unless an undesirably thick coating is used, the barrier is not sufficiently effective for food products requiring long shelf life. Such film forming lipids tend to become unstable under normal, practical use condition and lose film integrity and barrier effectiveness. In addition to structural instability, such as oiling out or cracking upon handling or with changes in temperatures, such lipid-based moisture barriers have disadvantages of being organoleptically unacceptable (greasy or waxy mouthfeel).
Accordingly, many of the barriers in the art use a water-impermeable lipid in association with hydrocolloids or polysaccharides such as alginate, pectin, carrageenan, cellulose derivatives, starch, starch hydrolysates, and/or gelatin to form gel structures or crosslinked semi-rigid matrixes to entrap and/or immobilize the nonaqueous or lipid material. In many cases these components are formed as bilayer films. These bilayer films may be precast and applied to a food surface as a self-supporting film with the lipid layer oriented toward the component with highest water activity. See, for example, U.S. Pat. No. 4,671,963 (Jun. 9, 1987), U.S. Pat. No. 4,880,646 (Nov. 14, 1987), U.S. Pat. No. 4,915,971 (Apr. 10, 1990), and U.S. Pat. No. 5,130,151 (Jul. 14, 1992). There are, however, a number of drawbacks associated with these moisture barriers. The hydrocolloids themselves are hydrophilic and/or water soluble and thus tend to absorb water with time. The absorption of water by the hydrophilic material in moisture barrier is greatly accelerated while the film is directly in contact with foods having a water activity (Aw) above 0.75. In addition, some hydrocolloids tend to make the barriers fairly stiff, requiring the addition of a hydrophilic plasticizer (e.g., polyol) to increase flexibility. These plasticizers are often strong moisture binder themselves thus promoting moisture migration into the barriers and decreased structural stability and effectiveness of the barriers. Furthermore, the texture and the required thickness of some of these barriers may make their presence perceptible and objectionable when the product is consumed. Additional processing steps (casting and drying) required to form these films make them difficult to use in high speed commercial production.
In the case of prepackaged grilled cheese sandwiches, a fat barrier is typically applied to the side of the bread facing the cheese, as described in U.S. Pat. No. 6,139,885. Moisture from the cheese can be transmitted through the air around the barrier to other parts of the bread, rendering the bread soggy. Even if sealing the part of the toast in contact with the cheese were sufficient to prevent moisture migration, the bread/toast has many nooks and crannies, making effective sealing of the surface for the purpose of moisture barrier extremely difficult under refrigerated conditions without an extremely thick coating of the barrier material. Thick coatings tend to be unpalatable to most consumers.
A particular type of barrier as described in U.S. Pat. No. 6,139,885 yields a more static layer that tends to remain in place to a greater extent after the cheese has melted. Hence, this type of barrier is more noticeable to the consumer. Application of the barrier to the toast results in a product that has a more noticeable barrier since the cheese does not flow next to it.

This patent is subject to a terminal disclaimer.

Microwaveable grilled cheese and meat sandwiches and method of preparation


Disclosed is an ink composition which comprises water, a colorant, and a monomeric oxazolidinone compound. In one embodiment, the oxazolidinone compound is of the formula ##STR1## wherein R.sub.1 is a hydrogen atom, an alkyl group, or a substituted alkyl group, and R.sub.2, R.sub.3, R.sub.4, and R.sub.5 each, independently of the others, are hydrogen atoms, alkyl groups, substituted alkyl groups, or alkoxy groups. Also disclosed are ink jet printing processes using the aforementioned ink.

The present invention is directed to aqueous ink compositions. More specifically, the present invention is directed to ink compositions suitable for use in ink jet printing processes. One embodiment of the present invention is directed to an ink composition which comprises water, a colorant, and a monomeric oxazolidinone compound.
Ink jet printing systems generally are of two types: continuous stream and drop-on-demand. In continuous stream ink jet systems, ink is emitted in a continuous stream under pressure through at least one orifice or nozzle. The stream is perturbed, causing it to break up into droplets at a fixed distance from the orifice. At the break-up point, the droplets are charged in accordance with digital data signals and passed through an electrostatic field which adjusts the trajectory of each droplet in order to direct it to a gutter for recirculation or a specific location on a recording medium. In drop-on-demand systems, a droplet is expelled from an orifice directly to a position on a recording medium in accordance with digital data signals. A droplet is not formed or expelled unless it is to be placed on the recording medium.
Since drop-on-demand systems require no ink recovery, charging, or deflection, the system is much simpler than the continuous stream type. There are two types of drop-on-demand ink jet systems. One type of drop-on-demand system has as its major components an ink filled channel or passageway having a nozzle on one end and a piezoelectric transducer near the other end to produce pressure pulses. The relatively large size of the transducer prevents close spacing of the nozzles, and physical limitations of the transducer result in low ink drop velocity. Low drop velocity seriously diminishes tolerances for drop velocity variation and directionality, thus impacting the system's ability to produce high quality copies. Drop-on-demand systems which use piezoelectric devices to expel the droplets also suffer the disadvantage of a slow printing speed.
The other type of drop-on-demand system is known as thermal ink jet, or bubble jet, and produces high velocity droplets and allows very close spacing of nozzles. The major components of this type of drop-on-demand system are an ink filled channel having a nozzle on one end and a heat generating resistor near the nozzle. Printing signals representing digital information originate an electric current pulse in a resistive layer within each ink passageway near the orifice or nozzle, causing the ink in the immediate vicinity to evaporate almost instantaneously and create a bubble. The ink at the orifice is forced out as a propelled droplet as the bubble expands. When the hydrodynamic motion of the ink stops, the process is ready to start all over again. With the introduction of a droplet ejection system based upon thermally generated bubbles, commonly referred to as the "bubble jet" system, the drop-on-demand ink jet printers provide simpler, lower cost devices than their continuous stream counterparts, and yet have substantially the same high speed printing capability.
The operating sequence of the bubble jet system begins with a current pulse through the resistive layer in the ink filled channel, the resistive layer being in close proximity to the orifice or nozzle for that channel. Heat is transferred from the resistor to the ink. The ink becomes superheated far above its normal boiling point, and for water based ink, finally reaches the critical temperature for bubble formation or nucleation of around 280.degree. C. Once nucleated, the bubble or water vapor thermally isolates the ink from the heater and no further heat can be applied to the ink. This bubble expands until all the heat stored in the ink in excess of the normal boiling point diffuses away or is used to convert liquid to vapor, which removes heat due to heat of vaporization. The expansion of the bubble forces a droplet of ink out of the nozzle, and once the excess heat is removed, the bubble collapses on the resistor. At this point, the resistor is no longer being heated because the current pulse has passed and, concurrently with the bubble collapse, the droplet is propelled at a high rate of speed in a direction towards a recording medium. The resistive layer encounters a severe cavitational force by the collapse of the bubble, which tends to erode it. Subsequently, the ink channel refills by capillary action. This entire bubble formation and collapse sequence occurs in about 10 microseconds. The channel can be refired after 100 to 500 microseconds minimum dwell time to enable the channel to be refilled and to enable the dynamic refilling factors to become somewhat dampened. Thermal ink jet processes are well known and are described in, for example, U.S. Pat. No. 4,601,777, U.S. Pat. No. 4,251,824, U.S. Pat. No. 4,410,899, U.S. Pat. No. 4,412,224, and U.S. Pat. No. 4,532,530, the disclosures of each of which are totally incorporated herein by reference.
U.S. Pat. No. 5,300,143 (Schwarz), the disclosure of which is totally incorporated herein by reference, discloses an ink composition which comprises water, a water soluble dye, a first component selected from the group consisting of sulfones and mixtures thereof, and a second component selected from the group consisting of cyclic amines having at least one hydrogen atom bonded to a nitrogen atom, cyclic amides having at least one hydrogen atom bonded to a nitrogen atom, diamides having at least one hydrogen atom bonded to a nitrogen atom, polyalkoxy-substituted amides having at least one hydrogen atom bonded to a nitrogen atom, polyimine-substituted amides having at least one hydrogen atom bonded to a nitrogen atom, and mixtures thereof. Also disclosed is an ink jet printing process employing these inks.
U.S. Pat. No. 5,223,026 (Schwarz), the disclosure of which is totally incorporated herein by reference, discloses a thermal ink jet printing process which comprises incorporating into a thermal ink jet printing apparatus an ink composition comprising a colorant and a liquid vehicle which comprises a mixture of water and an organic component selected from the group consisting of cyclic amides, cyclic esters, polyethoxy-substituted or polyimine-substituted amides, and mixtures thereof, and heating selected nozzles in the printing apparatus containing the ink, thereby causing droplets of the ink to be ejected in an imagewise pattern onto a substrate.
Organic solvents and humectants included in ink jet ink compositions have a number of requirements, including water miscibility, thermal stability, hydrolytic stability, low volatility, high boiling point, high surface tension, low viscosity, compatibility with colorants, and the like. Glycols and glycol derivatives are the most widely used solvents and humectants; these materials, however, tend to result in formation of ink compositions with undesirably high viscosities, resulting in less than optimum frequency response and latency when the inks are used in ink jet printing processes. Latency in particular becomes a more critical issue with the introduction of printheads having small channels and relatively high values of dots per inch.
Accordingly, while known compositions and processes are suitable for their intended purposes, a need remains for improved ink compositions suitable for use in ink jet printing processes. In addition, a need remains for ink compositions suitable for ink jet printing containing solvents or humectants with high water miscibilities. Further, a need remains for ink compositions suitable for ink jet printing containing solvents or humectants with high thermal stabilities. Additionally, a need remains for ink compositions suitable for ink jet printing containing solvents or humectants with high hydrolytic stabilities. There is also a need for ink compositions suitable for ink jet printing containing solvents or humectants with low volatilities. In addition, there is a need for ink compositions suitable for ink jet printing containing solvents or humectants with high boiling points. Further, there is a need for ink compositions suitable for ink jet printing containing solvents or humectants that are highly compatible with a large number of colorants, cosolvents, and ink additives. Additionally, there is a need for ink compositions suitable for ink jet printing containing solvents or humectants with low viscosities. A need also remains for ink compositions suitable for ink jet printing containing solvents or humectants with high surface tensions. There is also a need for ink compositions suitable for ink jet printing which have low viscosities. In addition, there is a need for ink compositions suitable for ink jet printing which exhibit improved latency characteristics. Further, a need remains for ink compositions suitable for ink jet printing which exhibit improved frequency response characteristics. Additionally, a need remains for ink compositions suitable for ink jet printing processes employing printheads with small channels and capable of printing 600 or more dots per inch. There is also a need for ink compositions suitable for ink jet printing processes which are toxicologically and environmentally safe. Further, there is a need for ink compositions suitable for ink jet printing which generate high quality images on paper. Additionally, there is a need for ink compositions suitable for ink jet printing which generate high quality images on transparencies.


A control circuit of an optical storage device includes a loop phase calculation unit for calculating a closed loop phase of a servo system according to at least one error signal of the servo system and a system control unit coupled to the loop phase calculation unit for generating an optimized control parameter according to the closed loop phase to perform compensation control, wherein the servo system comprises a tracking servo control system or a focusing servo control system, the compensation control is radial tilt control or focus balance adjustment, and the optimized control parameter is at least one optimized control parameter determined according to a plurality of closed loop phases calculated by the loop phase calculation unit.

An optical storage device is disclosed, and more particularly, a control circuit of an optical storage device and related method thereof is disclosed.
The advancements in computer processing speed and the development of the Internet have resulted in data storage requirements growing tremendously. Many optical discs, for example, digital versatile discs (DVD), are popular due to their characteristics of compact size, large storage capacity, and low price. Therefore, the corresponding optical storage devices, for example, the DVD drives or the DVD burners, are standard devices found in use with typical modern computers.
Please refer to FIG. 1, which is a diagram of a control circuit of a disc tilt control device inside an optical storage device according to US Patent Application Publication No. 2003/0147315. Please note that some devices are not shown in FIG. 1. The tilt control circuit at least comprises: a tracking error signal calculating unit 10, a loop level calculating unit 11, a system control unit 12, a radial tilt control unit 14, and a tracking servo unit 15. The tracking error signal calculating unit 10, the loop level calculating unit 11, and the tracking servo unit 15 can be utilized to form a tilt measuring device of a disc. The system control unit 12 can utilize detected loop level to represent the tilt amount and generate a control parameter according to the detected loop level to control the tilt angle between the disc 1 and the optical pickup head 3.
Please refer to FIG. 2, which is a detailed diagram of a tilt angle measuring device of the optical storage device shown in FIG. 1. As shown in FIG. 2, the portion indicated by a dashed line box is a detailed structure of the loop level calculating unit 11 shown in FIG. 1. The loop level calculating unit 11 comprises: band pass filters 1131 and 1141, full-wave rectifier 1132 and 1142, and low pass filters 1133 and 1143. The signal generator 112 can generate a disturbance signal of a sine wave. The output signal Vt generated by the tracking error signal calculating unit 10 is the conventional tracking error signal (TE signal). The loop level calculating unit 11 processes the TE signal and the signal added by the adder 111 through the band pass filters, the full-wave rectifier s, and the low pass filters to respectively obtain two loop level signals Vin and Vout. The ratio of the loop level signals Vout and Vin is the open loop gain. There is a corresponding relationship between the open loop gain and the tilt amount. Therefore, the system control unit 12 can obtain the corresponding relationship between the open loop gain and the control parameter according to the loop level signals Vin and Vout to control the tilt angle between the disc 1 and the optical pickup head 3.
As mentioned previously, the system control unit 12 can obtain the loop levels corresponding to several control parameters. The system control unit 12 can select an optimized tilt angle control parameter according to these loop levels. However, because the calculation of the loop gain of the optical storage device requires a divider, this is complex to implement.

Control circuit of optical storage device and method thereof


The present invention provides a method for further uniformly drawing out a carbon nanotube web while inhibiting mixing of edge scraps. A carbon nanotube web is drawn out from a carbon nanotube array-in a state in which abutting members which abut on the carbon nanotube array are provided on respective outer sides of both edges of a boundary region between the carbon nanotube array and the carbon nanotube web.

Carbon nanotubes are receiving attention as a material having excellent electrical conductivity, heat conductivity, and mechanical strength, and are increasingly used in various fields. In a case where the carbon nanotubes are utilized, the carbon nanotubes are sometimes formed into a film or a yarn in accordance with their utilization form.
Patent Literature 1 discloses a manufacturing method for obtaining a carbon nanotube film. The manufacturing method includes the following steps:    First step: Grow, on a substrate, a carbon nanotube array including a plurality of carbon nanotubes which are vertically arranged.    Second step: Form at least two grooves, which extend in parallel and are arranged apart from each other, on a surface of the carbon nanotube array which surface is opposite to a surface making contact with the substrate.    Third step: Fix, to a drawing device, ends of a plurality of carbon nanotubes which are included in the carbon nanotube array and are located between adjacent grooves.    Fourth step: Move the drawing device in a length direction of the grooves so as to detach the plurality of carbon nanotubes from the carbon nanotube array, and thus obtain at least one sheet of carbon nanotube film (corresponding to a carbon nanotube web in accordance with the present invention).
The second step of the manufacturing method is carried out in order to define a film width with which the carbon nanotube film is drawn out from the carbon nanotube array. That is, carbon nanotubes in the formed two grooves are disconnected from adjacent carbon nanotubes in an inner side region located between the two grooves. Therefore, in a case where the plurality of carbon nanotubes are drawn out from the inner side region, the carbon nanotubes in the grooves will not be drawn out while being connected with the carbon nanotubes in the inner side region. As a result, according to Patent Literature 1, the carbon nanotube film can be obtained which has a uniform width corresponding to the width defined by the two grooves.
Note that, as a specific example of the method for forming grooves, Patent Literature 1 discloses a laser method in which carbon nanotubes corresponding to a groove are irradiated with a laser beam. According to Patent Literature 1, carbon nanotubes irradiated with a laser beam become shorter in length by being destroyed with energy of the laser beam, and thus form a hollow portion, that is, a groove in a surface of the carbon nanotube array.

Method for drawing carbon nanotube web, method for manufacturing carbon nanotube yarn, method for manufacturing carbon nanotube sheet, and device for drawing carbon nanotube web


A method and system for managing traffic in a network. Label switch paths are identified. Each label switch path begins at a first provider edge and ends at a second provider edge. For each label switch path, logical paths are identified. Most recent data received from the first provider edge is transmitted to the second provider edge via a selected logical path.

Servers supporting mission-critical applications (i.e. financial transactions, database access, corporate intranets, etc.) must exchange traffic across data networks. Moreover, additional time sensitive applications (i.e. Voice over IP, Video) need to be carried across networks. Additionally, networks need the ability to scale performance to handle large numbers of end user requests without creating unwanted delays.
Network load balancing distributes traffic to multiple paths inside the network, each path going across different network equipment (Routers). Network load balancing transparently partitions the end user requests among the network paths.
Currently, the network routing protocols send traffic according to the shortest path between the end user and the application. Usually, the shortest path is determined based on static criteria such as least number of intermediate devices in the path (less hops), or larger capacity links (in terms of bandwidth). As the number of end users utilizing an application increases, the shortest path becomes congested.
MultiProtocol Label Switching (MPLS) refers to a mechanism which directs and transfers data between Wide Area Networks (WANs) nodes with high performance, regardless of the content of the data. MPLS belongs to the family of packet-switched networks. MPLS makes it easy to create "virtual links" between nodes on the network, regardless of the protocol of their encapsulated data. It can be used to carry many different kinds of traffic, including IP packets, as well as native ATM, SONET, and Ethernet frames. It is a highly scalable, protocol independent, data-carrying mechanism. Packet-forwarding decisions are made solely on the contents of the labels, without the need to examine the packet.
This allows one to create end-to-end circuits across any type of transport medium, using any protocol. The primary benefit is to eliminate dependence on a particular Data Link Layer technology, such as ATM, frame relay, SONET or Ethernet, and eliminate the need for multiple Layer 2 networks to satisfy different types of traffic. MPLS operates at an OSI Model layer that is generally considered to lie between traditional definitions of Layer 2 (Data Link Layer) and Layer 3 (Network Layer), and thus is often referred to as a "Layer 2.5" protocol. It was designed to provide a unified data-carrying service for both circuit-based clients and packet-switching clients which provide a datagram service model.
In MultiProtocol Label Switching networks, each service provider defines his own specific Quality of Service 'QOS' policy over its MPLS backbone. The mapping between the nature of traffic (real-time voice over IP, video streaming, http transactional, unidirectional, connection oriented, connection less) and the QOS policies of each service provider depends on the service provider QOS policy and is statically configured on each backbone edge router.
A drawback of such mapping is that it static and cannot be adjusted automatically on the service provider backbone usage and/or for any QOS policy modifications, thereby causing congestion.
Moreover, the real time and on-demand solutions massively deployed today at end user sites may conduct that a QOS policy provided by a service provider be considered rapidly obsolete.
The present invention solves the aforementioned problems.

Load balancing traffic in a MPLS network


A circular air flow pattern is created in a small oven cavity having a convection system including a convection cover which is mounted to and defines a duct in combination with a rear wall of the oven cavity. The convection cover includes an intake at one end portion arranged adjacent a first side wall of the oven cavity and a plurality of exhaust openings formed in another end portion arranged adjacent a second side wall of the oven cavity, with the convection cover progressively tapering through multiple sections. The rear wall can include an elongated recess over which the convection cover extends in forming the duct.

Field of the Invention
The present invention pertains to the art of cooking appliances and, more particularly, to a convection cooking system for an appliance having a small oven cavity.
Description of the Related Art
Conventional cooking appliances generally perform cooking operations through radiant heating developed from bake and/or broil elements. Such types of cooking appliances can take various forms, mainly ranges and wall ovens. While conventional or radiant heat cooking is suitable to a wide assortment of food types, the overall cooking process, especially baking, can be quite slow. The pre-heat time, combined with the cook time, is longer than most consumers desire.
Some radiant cooking appliances incorporate internal fans which can be used during certain cooking operations in order to generate an air flow within an oven cavity to enhance even cooking. Forced air convection allows for cooking at lower temperatures as compared to conventional radiant cooking processes. In addition, the forced air streams serve to disrupt a thermal insulation layer about the food item which increases the heat transfer rate between the food item and its surroundings, thereby reducing required cooking times.
In convection cooking appliances, the air flow can be designed to recirculate within the oven cavity, flow through the oven cavity and be exhausted, or a combination of both of these configurations. For obvious reasons, it is desirable to enhance the efficiency of any air flow system in order to reduce associated operating costs and minimize the required fan size, while still producing an effective air flow pattern and rate. Most convection systems employ a fan which draws cooking cavity air into a central intake portion and directs the air radially outward across a heating unit for re-introduction back into the oven cavity through plural, spaced exhaust outlets. Most often, the outlets are arranged either directly adjacent the side walls of the cooking cavity or the outlets are simply arranged in a generally circular configuration about the air inlet and angled toward the side walls. In either case, the air is exhausted along the side walls, flows forward towards a door for the oven cavity and then is re-directed into a central oven cavity region back to the fan intake.
With relatively large oven cavities, such as oven cavities of 4.0 cubic feet or more, the above-described air flow arrangement is quite effective. However, with smaller oven cavities in the order of 2.5 cubic feet or less, special spatial and air flow considerations are encountered. For instance, from just a dimensional standpoint, utilizing a conventional convection arrangement in a small oven cavity would result in the inlet and outlet portions being in close proximity which would tend to reduce the amount of air turnover inside the oven cavity. Therefore, regardless of the existence of numerous convection systems in the art, there exists a need for an enhanced convection air flow system for use in a cooking appliance, particularly a cooking appliance having a small oven cavity.

Convection cooking appliance with circular air flow system