Patent Application
20140209803
The present invention is in the field of mechanisms, including electrical circuits, for maintaining or providing a constant or substantially constant power to a predetermined electrical component, for reducing and/or minimizing power decay within power sources and/or electrical components, and for improving an infrared source driver or a power source in general. Such improvement of power delivery and minimization of power loss is important for precision instrumentation applications. One such application is the infrared (“IR”) source driver for optical instruments, and in particular infrared Spectrometers such as Fourier Transform Infrared Spectrometers (“FTIRs”).
FTIRs are well known in the art. Michelson interferometers function by splitting a beam of electromagnetic radiation into two separate beams via a beam splitter. Each beam travels along its own path, e.g., a reference path of fixed length and a measurement path of variable length. A reflecting element, such as a retroreflector, is placed in the path of each beam and returns both beams to the beam splitter. The beams are there recombined into a two exit beams. The variable path length causes the combined exit beams to be amplitude modulated due to interference between the fixed and variable length beams. One exit beam of the two exit beams may typically return towards the source, and in one or more designs may not used, although it contains practical information, and in one or more other designs may be used for such practical information. By analyzing the second exit beam, propagating away from the source, the spectrum of the input radiation may, after suitable calibration and calculation, be derived as a function of frequency.
When the above interferometer is employed in an FTIR Spectrometer, the used exit beam or exit beams are focused upon a detector. If a sample is placed such that the modulated beam passes through it prior to impinging upon the detector, the analysis performed can determine the absorption spectrum of the sample. The sample may also be placed otherwise in the arrangement to obtain other characteristics.
Silicon carbide and silicon carbide ceramics have long been used as an infrared (IR) source in Spectrometers. Preferably, in one or more applications, the IR source is bright and stable over one or more long periods of time, at a predetermined, constant temperature. However, it has been observed that the brightness of silicon carbide and silicon carbide ceramic sources decays rapidly over time when driven at constant voltage. The reason for the decay has been traced to an increase in electrical resistance over time. Since the electrical power delivered to the IR source at a constant voltage depends inversely on resistance, power delivered to the source also decays over time. Unless corrected by some means, an inferior mode of operation of the Spectrometer results because a reduction in source power reduces the signal level in the Spectrometer, thereby reducing the signal to noise ratio of the Spectrometer.
An unsatisfactory solution that has been employed in the past is to use a circuit that measures the voltage applied to the source and stabilizes the voltage. This is called constant voltage operation. Unfortunately, this problem is grossly inadequate. The inadequacy is easily illustrated by the following practical example: A 12 watt IR source might have a resistance of 12 Ohms when new and 40 Ohms when old. This is illustrated by actual measurements of a source in
An additional unsatisfactory solution is to use a photodetector staring at the IR source. It may be easy to think that using a photodetector is an ideal solution. Unfortunately, if the photodetector ages, or if particulate matter or some other object blocks the detector, the detector may erroneously deliver a weaker signal, causing a subsequent control circuit to heat the IR source up, which can damage and/or destroy the IR source. In addition, most detectors are intrinsically thermally sensitive, and accurate detectors require their own thermal stabilization.
Constant current operation might also be considered. However, calculations similar to that in paragraph 5 above show that, as the IR source ages, the power would then actually increase. This will quickly lead to catastrophic failure of the IR source. As such, constant current operation is not a solution to the aforementioned problems.
Therefore, what is needed is an improved component or source driver circuit to provide stable and constant power to the component or IR source and to maintain the constant power, thereby reducing and/or minimizing power decay due to various mechanisms within the IR source. Such needs are felt for improving broadband light sources (i.e., a light source that radiates over a broad wavelength range; also referred to as light source/beam, radiation source, thermal source, infrared source, radiation beam, radiation/light source, and radiation/light beam) in general.
Accordingly, it would be desirable to provide a constant power circuit for use in at least one optical assembly to achieve constant, stable power over a sufficient predetermined period of time at high efficiency and a reasonable cost of manufacture and maintenance.
Accordingly, it is a broad object of the invention to provide an electrical circuit or apparatus and a system, and methods of using same, to make an efficient, stable and constant power source driver, such as an infrared (IR) source driver.
A method of delivering or providing constant or substantially constant power may include dynamically controlling or changing at least one of a voltage and a current of a predetermined, electrical component such that an electrical power, which is at least one of provided or delivered to the predetermined component and consumed by the predetermined component, is at least one of: (i) identical or substantially similar to a predetermined, chosen or preset value of electrical power; and (ii) constant or substantially constant, thereby reducing, minimizing or eliminating power decay within the predetermined component. The dynamically controlling or changing step may further include at least one of: (i) changing only the voltage of the predetermined, electrical component while keeping the current of the predetermined, electrical component constant in response to the changing resistance of the predetermined, electrical component; (ii) changing only the current of the predetermined, electrical component while keeping the voltage of the predetermined, electrical component constant in response to the changing resistance of the predetermined, electrical component; and (iii) changing a combination of the voltage of the predetermined, electrical component and the current of the predetermined, electrical component in response to the changing resistance of the predetermined, electrical component. The predetermined, chosen or preset value of electrical power may be at least one of: a preset value of electrical power that the predetermined component consumes to operate; a preset value of electrical power that the predetermined component needs to operate; a value of electrical power that a user of the predetermined component has set for the predetermined component; a factory or manufactured setting of electrical power at which the predetermined component is designed to operate; and a value of electrical power to be constantly maintained and achieved for at least one of delivery to and use by the predetermined component.
The predetermined, electrical component may have a resistance that operates to change over time, thereby requiring the dynamic control or change of at least one of the voltage and the current of the predetermined component to provide or deliver constant or substantially constant power. The voltage of the predetermined, electrical component may operate to be dynamic, varied or changed in response to the changing resistance of the predetermined, electrical component. The voltage of the predetermined, electrical component may be varied or changed using the equation V=square root (“sqrt”) of the product of power and resistance (P*R), where V is voltage, P is the predetermined, chosen or preset value of electrical power and R is the varying or changing resistance of the predetermined, electrical component. The current of the predetermined, electrical component may operate to be dynamic, varied or changed in response to the changing resistance of the predetermined, electrical component. The current of the predetermined, electrical component may be varied or changed using the equation I=sqrt (P/R), where I is current, P is the predetermined, chosen or preset value of electrical power and R is the varying or changing resistance of the predetermined, electrical component. The resistance of the predetermined, electrical component may change as a function of the amount of time that the predetermined, electrical component is used or operated. In at least one embodiment, the predetermined, electrical component may include at least one of: a broadband thermal infrared source, a radiation source, an infrared source, a broadband light source, a light source that radiates on a broadband wavelength, a light source or device for producing a light beam, a thermal source, and a device for producing a radiation beam. The electrical power that is at least one of delivered to and consumed by the predetermined, electrical component may originate from a power source.
The one or more methods may further include: (i) determining at least one of the electrical power at least one of consumed by and delivered or provided to the predetermined component and a value proportional to the electrical power at least one of consumed by and delivered or provided to the predetermined component by multiplying and obtaining a product of at least two signals, wherein: a first signal of the at least two signals at least one of represents and is proportional to the voltage of the predetermined component and a second signal of the at least two signals at least one of represents and is proportional to the current of the predetermined component; (ii) comparing at least one of the determined at least one of consumed and delivered electrical power and the determined multiplication product representing the at least one of consumed and delivered electrical power with the predetermined, chosen or preset value of electrical power; and (iii) adjusting, maintaining, creating or producing at least one of the voltage and current of the predetermined component based on at least one of the at least two signals, the multiplication product and the predetermined, chosen or preset value of electrical power such that the electrical power that is at least one of delivered to and consumed by the predetermined component is at least one of: identical or substantially similar to the predetermined, chosen or preset value of electrical power; and constant or substantially constant. The determining, comparing and adjusting, maintaining, creating or producing steps may be performed in a closed-loop control circuit and/or system, and/or may be performed continuously and repeatedly while the predetermined component is operating.
The methods may further include at least one of: (i) computing, calculating and/or creating at least one of: (a) the voltage of the predetermined component; (b) a voltage that is proportional to the electrical power that is at least one of consumed by and delivered to the predetermined component; (c) the current of the predetermined component; (d) a current that is proportional to the electrical power that is at least one of consumed by and delivered to the predetermined component; (e) the first signal of the at least two signals; and (f) the second signal of the at least two signals; (ii) obtaining or receiving the predetermined, chosen or preset value of the electrical power from at least one of a processor and a database in connection with a circuit and/or system operating the method to deliver or provide the constant or substantially constant power to the predetermined component; (iii) obtaining, receiving or setting the predetermined, chosen or preset value of the electrical power using a potentiometer (“pot”) of at least one of a circuit and a system operating the method to deliver or provide the constant or substantially constant power to the predetermined component; (iv) determining at least one of: (a) whether to increase, decrease or keep constant at least one of the voltage of the predetermined component, the current of the predetermined component, the voltage that is proportional to the electrical power that is at least one of consumed by and delivered to the predetermined component, the current that is proportional to the electrical power that is at least one of consumed by and delivered to the predetermined component, the first signal of the at least two signals and the second signal of the at least two signals; (b) if a need for an increase or decrease is determined, at least one of the amount of the increase or the decrease of at least one of: the voltage of the predetermined component, the current of the predetermined component, the voltage that is proportional to the electrical power that is at least one of consumed by and delivered to the predetermined component, the current that is proportional to the electrical power that is at least one of consumed by and delivered to the predetermined component, the first signal of the at least two signals and the second signal of the at least two signals; and (c) the final corrected value of at least one of the voltage of the predetermined component, the current of the predetermined component, the voltage that is proportional to the electrical power that is at least one of consumed by and delivered to the predetermined component, the current that is proportional to the electrical power that is at least one of consumed by and delivered to the predetermined component, the first signal of the at least two signals and the second signal of the at least two signals; (v) automatically adjusting, maintaining, creating or producing at least one of the voltage of the predetermined component, the current of the predetermined component, the voltage that is proportional to the electrical power that is at least one of consumed by and delivered to the predetermined component and the current that is proportional to the electrical power that is at least one of consumed by and delivered to the predetermined component in one or more increments, wherein the closed-loop operates to electrically perform the automatic maintenance, adjustment or production cyclically over time while the predetermined component is in operation; and (vi) sending at least one of the determined electrical power that is at least one of consumed by and delivered to the predetermined component, the at least two signals and the multiplication product to a control circuit or control system operating the method to deliver or provide the constant or substantially constant power to the predetermined component.
One or more further methods may further include at least one of: (i) measuring at least one of the voltage of the predetermined component and a signal proportional to the voltage of the predetermined component to obtain a first value; (ii) measuring at least one of the current of the predetermined component and a signal proportional to the current of the predetermined component; (iii) creating a voltage proportional to at least one of the current and the signal proportional to the current, the voltage proportional to at least one of the current and the signal proportional to the current having a second value; (iv) multiplying and obtaining a product of at least one of the measured voltage and the measured current and the first and second values, thereby obtaining a value that is proportional to the at least one of consumed and delivered electrical power; (v) comparing the determined value that is proportional to the at least one of consumed and delivered electrical power with the predetermined, chosen or preset value of electrical power; and (vi) adjusting, maintaining, creating or producing at least one of the current, the voltage, both the current and the voltage, and the product of the voltage times current delivered to the predetermined electrical component such that the electrical power that is at least one of delivered to and consumed by the predetermined component is at least one of: identical or substantially similar to the predetermined, chosen or preset value of electrical power; and constant or substantially constant. The measured at least one of the voltage of the predetermined component and the signal proportional to the voltage of the predetermined component may be available or stored as a digital number, and/or the measured at least one of the current of the predetermined component and the signal proportional to the current of the predetermined component may be available or stored as a second digital number. The first and second values may be converted to first and second digital numbers by at least one analog-to-digital converter (ADC). The measuring, measuring, creating, multiplying and adjusting, maintaining, creating or producing steps may be performed continuously and repeated while the predetermined component is operating.
The first and second digital numbers may be multiplied using a digital multiplier, thereby obtaining a number that is proportional to the at least one of consumed and delivered electrical power. The digital multiplier may be included in a computer or processor that operates to use the multiplied number output from the digital multiplier to perform a processing step for generating a digital-to-analog converter (DAC) command, the DAC command being transmitted to a DAC, which generates an analog output that is transmitted to a power stage, the power stage also receiving a commanded power from the processing step of the computer or processor and using the commanded power and the analog output from the DAC to perform the adjusting, maintaining, creating or producing step. The measuring, measuring, creating, multiplying and adjusting, maintaining, creating or producing steps may be performed by at least one of the computer or the processor and one or more processors or computers. The measuring voltage step may be performed by a voltage measuring circuit and the measuring current step may be performed by a current measuring circuit, and the measuring, measuring, creating, multiplying and adjusting, maintaining, creating or producing steps may be performed in a closed-loop circuit and/or system. At least one of the computer or the processor and the one or more processors or computers may execute the measuring, measuring, creating, multiplying and adjusting, maintaining, creating or producing steps by: (a) creating one or more new command numbers for one or more variables to be controlled, the one or more variables comprising at least one of: the current, the voltage, both the current and the voltage, and the product of the voltage times current delivered to the predetermined electrical component; and (b) applying the one or more new command numbers to one or more digitally responsive circuits, thereby controlling the one or more variables. The one or more digitally responsive circuits may include digital-to-analog converters (DACs) that operate to create at least one of the output voltages and the output currents.
The signals that are proportional to at least one of the voltage, the current and the at least one of consumed and delivered electrical power may be generated by at least one logarithmic amplifier and an antilogarithmic amplifier, the at least one logarithmic amplifier operating to generate a voltage proportional to log (the voltage of the predetermined component) and a voltage proportional to log (the current of the predetermined component) and to transmit the generated voltages to a summing amplifier, the summing amplifier operating to sum the two generated voltages, thereby creating a voltage proportional to the log of the current times the voltage, and the antilogarithmic amplifier operating to receive the voltage proportional to the log of the current times the voltage and to create a voltage proportional to the at least one of consumed and delivered electrical power.
In accordance with one or more aspects of the present invention, one or more power control circuits and/or systems (also referred to as a “power circuit”) for delivering or providing constant or substantially constant power are provided. It is a further purpose of this invention to produce substantially constant and stable power via a novel, unobvious circuit, especially for an IR source driver or other type of source driver. Surprisingly it has been found that uniquely combining two integrated circuits provides the solution to the aforementioned power decay problem such that substantially constant, stable power may be achieved.
One or more power control circuits and/or systems may include at least one of at least one circuit and at least one processor, at least one of the at least one circuit and the at least one processor operating to perform one or more of the aforementioned methods to dynamically control or change at least one of a voltage and a current of a predetermined, electrical component such that an electrical power, which is at least one of provided or delivered to the predetermined component and consumed by the predetermined component, is at least one of: (i) identical or substantially similar to a predetermined, chosen or preset value of electrical power; and (ii) constant or substantially constant. Preferably, the predetermined, electrical component is connected to, and communicates with, the at least one of the at least one circuit and the at least one processor, and the at least one of the at least one circuit and the at least one processor may be connected to, and in communication with, the power source operating to provide the electrical power. Preferably, the one or more power control circuits and/or systems operate in a closed-loop, and at least one of the at least one circuit and the at least one processor operate in a closed-loop. At least one of the at least one circuit and the at least one processor may operate to at least one of receive and set a new value for the predetermined, chosen or preset value of electrical power.
In one or more embodiments, the at least one of the at least one circuit and the at least one processor may further include at least one of a first circuit and a first processor and at least one of a second circuit and a second processor, wherein: (i) the at least one of the first circuit and the first processor operates to determine the at least one of consumed and delivered electrical power, to receive the at least two signals, to calculate the value proportional to the electrical power by multiplying and obtaining a product of the at least two signals, and to send at least one of the at least two signals, the multiplication product and the calculated at least one of consumed and delivered electrical power to the at least one of the second circuit and the second processor; and (ii) the at least one of the second circuit and the second processor operates to: (a) compare at least one of the determined electrical power that is at least one of consumed and delivered to the predetermined component, the at least two signals, and the determined multiplication product representing the at least one of consumed and delivered electrical power with the predetermined, chosen or preset value of electrical power; and (b) adjust, maintain, create or produce at least one of the voltage and current of the predetermined component based on at least one of the at least two signals, the multiplication product and the predetermined, chosen or preset value of electrical power such that the electrical power that is at least one of delivered to and consumed by the predetermined component is at least one of: identical or substantially similar to a predetermined, chosen or preset value of power; and constant or substantially constant, thereby reducing, minimizing or eliminating power decay within the predetermined component. The at least one of the second circuit and the second processor may further operate to at least one of: (i) automatically and continuously repeat the comparison of the information received from the at least one of the first circuit and the first processor and the adjustment, maintenance or production of the at least one of the voltage and current of the predetermined component; and (ii) automatically and continuously repeat the comparison of the information received from the at least one of the first circuit and the first processor and the adjustment, maintenance or production of the at least one of the voltage and current of the predetermined component while the predetermined component is operational. The at least one of the at least one first circuit and the at least one first processor may include at least one of: an integrated circuit, a MAX 4210B, a MAX 4210, a MAX 4211, a computer, one or more processors, one or more microprocessors, and one or more analog-to-digital converters with one or more analog conditioning circuits, and the at least one of the at least one second circuit and the at least one second processor may include at least one of: an integrated circuit; a MAX15041, a switching regulator, and a closed-loop switching regulator, a computer, one or more processors and one or more microprocessors.
In one or more embodiments, two integrated circuits (e.g., the two commercially available integrated circuits discussed below) may be employed in a novel way to make an efficient constant power IR source driver. The first circuit, i.e., the MAX15041 or a similar circuit, may be purchased from Maxim Integrated (www.maximintegrated.com). The first circuit may be a switching regulator that may be used to regulate voltage. The MAX15041 uses synchronous DC-DC conversion to achieve good efficiency over a wide range of output voltages. The MAX 15041 is a low-cost, synchronous DC-DC converter with internal switches that can deliver an output current up to 3A. In one or more embodiments of the invention, the MAX15041 may be used as a voltage regulator where the output voltage is controlled in such a way as to regulate the power dissipated in a predetermined component, such as an IR source.
The second circuit may be a MAX 4210B or a similar circuit (e.g., the MAX 4210/MAX 4211) that may also be purchased from Maxim Integrated (www.maximintegrated.com) or other circuit discussed below or a similar circuit thereto and which outputs a voltage that is proportional to power consumed. It will be appreciated that, with advances in semiconductor circuit offerings, differing, superior or lower cost circuits, having substantially identical functions, but which may differ in internal construction, may be suitably applied to the described invention.
Typically, these types of products lack power regulation or have inefficient means of power regulation. Additionally, these products, as they are typically used, exude massive or large amounts of heat, which leads to inefficient loss of power. However, as will be described below, the combination of the aforementioned circuits, or similar circuits, will be operated to construct a constant power delivery circuit with high accuracy, and also high efficiency, where efficiency is defined as the ratio of the delivered power to the source divided by the overall electrical power delivered to the circuit powering the source. As a further novel and non-obvious aspect of this invention, the signal (e.g., such as a signal proportional to power) created by the second circuit, e.g., the MAX 4210B or a similar circuit, is sent to the first circuit, e.g., the MAX15041 or a similar circuit (e.g., a similar circuit having an efficient power stage), at the feedback terminal of the first circuit. Such a unique, non-obvious combination of integrated circuits results in the critical results of having stable, constant, substantially stable or substantially constant power output (see e.g.,
The at least one of the second circuit and the second processor may further include at least one closed-loop switching regulator to produce at least one of the varied or changed voltage and the varied or changed current to operate the predetermined component. The switching regulator or the at least one closed-loop switching regulator may include a first regulator and a second regulator, the first regulator operating to produce the varied or changed voltage and the second regulator operating to produce the varied or changed current. The first regulator may be at least one of: a voltage regulator, a voltage switching regulator, a voltage regulator with an operational amplifier (“op amp”), a transistor regulator, silicon controlled rectifiers (“SCR”), a voltage stabilizer and the MAX15041. The first regulator may operate to employ synchronous DC-DC conversion to achieve efficiency over a wide range of output voltages and/or currents of the predetermined component. The second regulator may be at least one of: a transistor, a current regulator, an operational amplifier (“op amp”), a field-effect transistor, a junction gate field-effect transistor (“JFET”), a current source, a current source with thermal compensation, a voltage regulator current source, and the MAX15041. The first regulator, the second regulator and the pot may be connected to, and in communication with, the predetermined component. The pot may include a three-terminal resistor with a sliding contact that operates as a voltage divider to be used to set the predetermined power value for the predetermined component, and may operate to set or modify the predetermined, chosen or preset value of electrical power.
The one or more power control circuits and/or systems may further include at least one of: (i) one or more analog-to-digital converters operating to convert at least one of the at least two signals, the multiplication product and the information from analog and digital; and one or more digital-to-analog converters operating to convert at least one of the at least two signals, the multiplication product and the information from digital to analog; (ii) one or more analog-to-digital converters and one or more digital-to-analog converters when one or more of the computers are in use, such that the one or more of the computers operate to sense current and/or voltage of the predetermined component with the one or more analog-to-digital converters and to provide at least one of command voltage and current to the switching regulator with the one or more digital-to-analog converters; and (iii) at least one of: a printed circuit board (“PCB”) or a prototype board; one or more capacitors; at least one inductor; at least one resistor; one or more additional voltage regulators; one or more additional current regulators; at least one snubbing network; one or more pads for use with the at least one snubbing network, the at least one resistor and the one or more capacitors; at least one of a 78L05 voltage regulator and regulator or transistor using a T0-92 structure; and a loop compensation network. The one or more capacitors may include at least six capacitors. The at least one inductor may include at least one of a 47 uH inductor, a 100 uH inductor, a 39 uH inductor, a Digi-Key 587-1700-1-ND, an inductor having an inductance in the range of about 39 uH to about 100 uH. The at least one resistor may include at least one of a 0.091 Ohm resistor and a Digi-Key RL16R.091FCT-ND.
Additionally, the one or more power control circuits and/or systems may further include a predetermined path for the at least one of consumed and delivered electrical power to travel through the power control circuits and/or systems, a first ground connection running under the PCB or the prototype board and a second ground connection running next to the power path, wherein the power path is straight and direct or substantially straight and substantially direct over the structure of the PCB or the prototype board, the first and second ground connections are disposed at the extended paddle (“EP”) under the at least one of the at least one second circuit and the at least one second processor and the EP operates to conduct heat. Additionally or alternatively, the one or more power control circuits and/or systems may further include at least one of at least one power regulator and one or more power sensors, the one or more power sensors operating to confirm that the electrical power being at least one of delivered to and consumed by the predetermined component is remaining constant or substantially constant.
It is a further object of the invention to provide a constant power IR source driver for supplying constant, stable power or substantially constant, stable power to an optical assembly, such as a Spectrometer, or one or more components thereof. The constant power circuit and/or system may be used in at least one optical instrument, such as a Fourier Spectrometer, to create an optical spectrum from a light/radiation beam and/or electrical signal created from the beam. Indeed, it is a further object of the present invention to provide an improved performance Fourier Spectrometer and/or an improved broadband light source (i.e., a light source that radiates on a broadband wavelength; also referred to as light source/beam, radiation source, radiation beam, radiation/light source, and radiation/light beam) incorporating a broadband thermal source, employing the power circuit described. In one or more embodiments, the Fourier Spectrometer may include: a Fourier modulator including a Michelson interferometer; a broadband and/or thermal light source collimated by a first optical system and incident on the Michelson interferometer therein; a second optical system collecting light transmitted by the Michelson interferometer and transmitting it to a sample region; a third optical system collecting light from the sample region and focusing it into a detector region; an optical detector located in the detector region converting the transmitted light from the sample region into an electrical signal; a power control circuit and/or system of the present invention operating to stabilize the broadband and/or thermal light source by delivering or providing a constant or substantially constant power to the broadband and/or thermal light source; and a Fourier analyzer comprising one or more electronics and software that operate to convert the electrical signal into an optical spectrum.
It is a further purpose of this invention to provide a non-transitory computer-readable storage medium containing software code operating to cause one or more of a plurality of processors to perform any of the methods of the present invention.
Other objects of the invention will in part be understandable and will in part be apparent from the following description.
For the purposes of illustrating the various aspects of the invention, wherein like numerals indicate like elements, there are shown in the drawings simplified forms that may be employed, it being understood, however, that the invention is not limited by or to the precise arrangements and instrumentalities shown. To assist those of ordinary skill in the relevant art in making and using the subject matter hereof, reference is made to the appended drawings and figures, wherein:
A power control circuit or apparatus, a power control system, a Fourier Spectrometer for use with the power control circuit or apparatus, power control system and method(s) of using same are disclosed herein. The power control circuit or apparatus operates as a predetermined component driver or a source driver to provide a constant, stable or substantially constant or stable supply of power to a predetermined component, such as a radiation source.
Turning now to the details of the figures,
Detector 60 measures the interference between the two radiation beams emanating from the single radiation source. These beams have, by design, traveled different distances (optical path lengths), which creates a fringe effect which is measurable by detector 60.
Radiation source 110 can be collimated white light for general interferometry applications, such as optical surface profiling, collimated infrared light for an infrared Spectrometer, a single collimated radiation intensity laser light source, etc., for accurate distance measurements or any now known, or which become known in the future, light/radiation source used in spectroscopy. Additionally or alternatively, For operation as a Fourier Transform Spectrometer, radiation source 110 may be a broadband light source (i.e., a light source that radiates in a broad band of wavelengths; also referred to herein as (and used interchangeably with) “light”, “light source”, “radiation”, “light source/beam”, “radiation source”, “radiation beam”, “radiation/light source”, “thermal source” and “radiation/light beam”).
Movable reflecting assembly 150 may utilize a hollow corner-cube retroreflector 152. The hollow corner-cube retroreflector 152 could be made in accordance with the disclosure of U.S. Pat. No. 3,663,084 to Lipkins, herein incorporated by reference.
Retroreflector 152 is mounted to a movable base assembly 144, which assembly allows for adjustment of the location of retroreflector 152 in a line along the path of beam 120. The displacement of assembly 144 is adjustable; e.g., through use of adjusting knob 146. Other means of moving assembly 144 are also anticipated by the invention, including such means that might allow for continuous, uniform movement of assembly 144. For example, means of movement of assembly 144 might be accomplished in accordance with the structure described in U.S. Pat. No. 5,335,111 to Bleier, herein incorporated by reference, or by co-pending application Ser. No. 12/505,279 filed on Jul. 17, 2009.
The use of retroreflector 152 as the movable reflecting assembly 150 allows for any angular orientation of retroreflector 152 as long as edge portions of the retroreflector mirrors do not clip a portion of beam 120.
From the foregoing, the length of the beam paths 20, 22 and 26 are fixed and known while the length of beam path 24 may be varied. The variation of the length of beam path 26 is, of course, critical to the operation of the interferometer, as is knowing the length as precisely as possible.
A monolithic optical assembly 200, as seen in
As shown in
Beamsplitter 130 may be comprised of two panels bonded to each other along a common surface. The common surface is an optically flat reflecting surface having a beamsplitter coating thereon. Beamsplitter 130 is bonded along portions of top edges 137 to portions of bottom surface 267 of top plate 260, and along portions of bottom edges 138 to portions of top surface 278 of bottom plate 270. One panel of beamsplitter 130 is a compensating member. The purpose of the compensating panel is to equate the material portions of the optical path difference of the two beams created by the beamsplitter. Without the compensating panel, the beam transmitted through the beamsplitter would travel through the optical material of the beamsplitter twice, while the reflected beam would travel through optical material zero times. By adding a compensating panel, ideally of the same thickness, wedge, and material as the beamsplitter, both beams travel twice through equal portions of optical material before being recombined at the beamsplitter surface, thereby equating any differences they may have experienced in that portion of their optical path length through material. The invention also anticipates a structure where the compensating panel is separated from the beamsplitter.
The support combination of first support member 210, second support member 220 and beamsplitter 130 between top plate 260 and bottom plate 270 creates a monolithic structure. As earlier discussed, it is also possible to have third support member 230 situated between portions of third edge surfaces 266 and 276 of top and bottom plates 260 and 270, respectively, as seen in the figures.
To complete the required reflecting elements of a Michelson interferometer, it is seen in the figures that a mirror panel 140 is bonded to a portion of top surface 278 of bottom plate 270, and to a second edge surface 214 of support member 210. Mirror panel 140 is slightly over hanging top surface 278 of bottom plate 270 by a portion of a bottom edge surface of mirror panel 140, and is bonded between these touching surfaces. Bonding also takes effect between the side edge surface of mirror panel 140 that touches edge surface 214 of support member 210. Bonding must avoid distorting the optically flat nature of the reflecting surface 142 of mirror panel 140.
Since mirror panel 140 is fixedly attached to assembly 200, as has just been discussed, there is no necessity for panel 140 to be other than a single, flat paneled mirror; for example, panel 140 does not need to be a retroreflector. One of the benefits of using a retroreflector (as has been discussed earlier regarding movable reflecting assembly 150 and as discussed further below) in a structure is that the orientation of the retroreflector is unimportant. The secured mounting of panel 140 to the monolithic structure assures that the orientation of panel 140 will not fluctuate due to vibration and shock, and therefore, a retroreflector is unnecessary (although a retroreflector alternatively could of course be utilized).
The portion of beam 120 that passes through beam splitter 130 and interacts with retroreflector 152 may also be returned via a second mirror panel, similar to mirror panel 140. This second mirror panel may be made integral with second support member 220 or be a separate panel supported by one or all of the second support member 220, edge 264 of top plate 260 and bottom plate 270.
Assembly 200 can also have a fourth support member 240. While the main purpose of fourth support member 240 is not to help stabilize the monolithic structure of assembly 200, it is nevertheless called a support member herein. Instead, fourth support member 240 is positioned in relation to the path traveled by beam 120 so as to allow beam 120 to pass through opening 242 in member 240, to travel between beamsplitter 130 and movable reflecting assembly 150. One or both of elements 244, 246 can comprise reflecting elements for returning beam 120 to retroreflector 252.
All members 210, 220, 230, 240, 260, 270, 130 and 140, of assembly 200, may be made of the same material. The material preferably being fused quartz or annealed Pyrex (e.g., any type of annealed borosilicate glass and/or glasses having a low coefficient of thermal expansion). The use of identical materials allows the coefficients of expansion of the materials to be identical, so that any temperature changes experienced by assembly 200 is experienced equally throughout each member to allow assembly 200 to expand and contract uniformly, thereby substantially removing distortions in the reflecting surfaces of beamsplitter 130 and mirror panel 140.
The monolithic construction discussed above has the benefit of high thermal stability in its optical alignment. This stability derives from the construction of the unit from a single, low expansion material such as Pyrex glass (e.g., any type of annealed borosilicate glass and/or glasses having a low coefficient of thermal expansion), fused silica, Zerodur or Cervit. However, in the application of infrared Fourier transform spectroscopy, often called FTIR, it may not be possible to fabricate the beamsplitter and compensating plate or panel 130 from the same material as the assembly. This may occur when the need for high transmission in the infrared (“IR”) is not consistent with available low expansion structural materials. In particular, the high IR transmission optical material may have a much higher thermal expansion coefficient.
Attaching optical elements having a thermal expansion coefficient different from the expansion coefficient of the remainder of the assembly could introduce wavefront distortion in the interfering optical beams or even result in mechanical failure under temperature changes. In order to take advantage of the permanent optical alignment afforded by a monolithic assembly, the connection between optical elements, e.g., beamsplitter and compensating plate or panel 130, and the rest of the monolithic assembly should transmit minimal stress from this assembly to the optical elements under temperature changes.
Not only are the circuits, apparatuses, systems and methods described herein unique, but the various aspects of the present invention are also nonobvious. The aforementioned, deficient methods are not capable of operating over the broad, required voltage range needed to provide constant power to a component, such as an IR source, having a resistance that is changing (e.g., increasing, decreasing, oscillating, etc.) over time. Indeed, the conventional wisdom in the art has been a lack of concern over (i.e., has been not to address) the delivery of responsive amperage when addressing the power loss problem. However, the present invention operates to provide responsive (e.g., dynamic or changing) amperage, and is not limited by the delivery of such amperage. For example, when load resistance is low, one or more embodiments of the circuit, apparatus, system, etc. of the present invention operate to deliver power levels needed for achieving constant or substantially constant power operation. Such delivery may occur at lower voltages than the input power source but at higher amperage than the input power source would be capable of. As the load resistance (e.g., the resistance of the component, such as the IR source) rises with age (as further explained above and below), the circuit delivers the same or substantially the same power to the load resistance, by controlling a combination of dynamic or changing voltage and dynamic or changing amperage. In at least one embodiment, the circuit, system, apparatus, etc. may be limited only by the input power source voltage. In other words, the one or more circuits, apparatuses, systems and methods of the present invention dynamically deliver varying voltages and currents, and may do so in accordance with the following equations:
V=sqrt(P*R) I=sqrt(P/R),
where P is the chosen constant or substantially constant power and R is the varying load resistance (e.g., the varying or changing resistance of the component, such as the IR source). Preferably, the power consumed by and/or delivered to the predetermined component is at least one of: (i) identical or substantially similar to the predetermined, preselected or chosen value of power; and (ii) constant or substantially constant. In one or more embodiments, the predetermined, electrical component (e.g., the radiation source 110) may have a resistance that changes over time, thereby requiring the dynamic control or change of at least one of the voltage and the current of the predetermined component (e.g., the radiation source 110) for providing or delivering constant or substantially constant power. The voltage may operate to be dynamic or changing in response to a changing resistance of the predetermined electrical component (e.g., the radiation source 110), and the current may operate to be dynamic or changing in response to a changing resistance of the predetermined electrical component (e.g., the radiation source 110), and both the voltage and current may operate to be dynamic or changing at once (i.e., both varying contemporaneously) in a dynamic or changing manner in response to a changing resistance of the predetermined electrical component (e.g., the radiation source 110). The step of controlling or changing the varying voltages and currents may further include at least one of: (i) changing only the voltage while keeping the current constant in response to a changing resistance of the predetermined, electrical component; (ii) changing only the current while keeping the voltage constant in response to a changing resistance of the predetermined, electrical component; and (iii) changing a combination of the voltage and the current in response to a changing resistance of the predetermined, electrical component.
In accordance with at least one aspect of the present invention, a method for driving a power source in a stabilized and electrically efficient manner is provided (as shown in
The determining step (see step 9001 of
Alternatively, in at least one embodiment where one or more of the steps are performed digitally, the computing, calculating and/or creating step may not employed or may be skipped. For example, the voltage, or a signal proportional to the voltage, delivered to the predetermined component may be measured and available, or stored, as a digital number. Typically, this is done by an analog-to-digital converter (also referred to as an “ADC”). Similarly, the current, or a signal proportional to the current, delivered to the predetermined component may be measured. Such a measurement step may further include a first step of creating a voltage proportional to the current, and a second step of converting that voltage to a number using an ADC. Having the two numbers, a computer or a processor (e.g., the computer or processor 1104 as further discussed below) then multiplies the two numbers together to form a number proportional to power. Based on this computed power, which is truly a measured power given the high accuracies of the mentioned ADC devices and methods, the computer or processor (e.g., the computer or processor 1104 as further discussed below) operates to alter at least one of the current, the voltage, and both the current and the voltage (or the product of voltage times current) delivered to the predetermined electrical component. The computer (e.g., the computer or processor 1104 as further discussed below) may execute such steps by creating one or more new command numbers for the one or more variables to be controlled, where the variables are at least one of the current, the voltage, and both the current and the voltage (or the product of voltage times current) delivered to the predetermined electrical component, and applying these numbers to one or more digitally responsive circuits, such as digital-to-analog converters (also referred to individually as a “DAC” or collectively as “DACs”), for the purpose of controlling these physical output variables. In one or more embodiments, the output voltages and/or currents of the DAC circuits may require supplementation in order to properly drive a predetermined electrical component at a constant or substantially constant power level. In such an instance, the supplementation may be provided via one or more power output stages to attain a constant or substantially constant power level. By way of example of at least one embodiment having one or more steps performed digitally, an analog output of a DAC circuit, whose value has been computed by a computer, may be wired directly to the aforementioned MAX15041 to represent the power (rather than the analog output of the MAX4210).
The comparing step (see Step 9002 of
The adjusting step (see Step 9003 of
Additionally or alternatively, the aforementioned signals that are proportional to at least one of the voltage, the current and the power may be generated by a logarithmic amplifier and a antilogarithmic amplifier. A first logarithmic amplifier may be used to generate a voltage proportional to log (the voltage of the predetermined component, such as the radiation source 110), and a second logarithmic amplifier may be used to generate a voltage proportional to log (a current passing through the predetermined component, such as the radiation source 110). A summing amplifier may then be used to sum these two voltages, thereby creating a voltage proportional to the log of the current×voltage (i.e., the product of current and voltage). Finally, the antilog amplifier may be used to create a voltage proportional to power.
Preferably, the control circuits 510 (three embodiments of which are shown in
Preferably, a first circuit and/or integrated circuit 511 (best seen in
The first circuit or integrated circuit (e.g., the integrated circuit 511) may include at least one switching regulator and/or at least one closed-loop switching regulator to produce at least one of the varied or changed voltage and the varied or changed current to operate the predetermined component at constant or substantially constant power. The switching regulator and/or the at least one closed-loop switching regulator (see e.g., element 511 of
In accordance with at least one aspect of the present invention,
In at least one embodiment, one or more components of the combined integrated circuit (e.g., the control circuit 510) may be employed as follows: The six (6) capacitors (see elements 520 in
While in at least one embodiment (see the system 600 in
While the loop compensation network on pin 4 of the MAX15041 may change from one embodiment of the circuit to the next, the network on pin 4 as shown in
Preferably, the power path is as straight and direct as possible over the topography or structure of a printed circuit board (“PCB”) (or of a socketed prototyping board, which may be alternatively used for a PCB in one or more embodiments, such as, but not limited to, the prototyping board 668 in
In one or more embodiments, the 78L05 (element 524 in
Those skilled in the art will also appreciate that further modifications may be made to the schematics shown in
In general, it may be desirable to limit the power level to the predetermined component, such as the IR source (e.g., the radiation source 110), to a range of values such that damage to the predetermined component is prevented while maintaining adjustment sensitivity. For example, as shown in
While a control circuit or system may be based on the circuits 510 shown in
In accordance with an aspect of the present invention, the constant power driver, circuit, and/or system (e.g., circuit 510, system 600, etc.), and methods of using same, may operate to deliver 12 watts (or any other predetermined value of constant or substantially constant electrical power as described above) in all cases (or in certain scenarios), thereby solving the “aging source problem” discussed above. Preferably, the system 600 includes a power regulator 632. Additionally, the system 600 may use a power sensor 664 (or more than one power sensor 664) on the PCB or the prototyping board 668 to help regulate the power, and, in the very least, to confirm that the electrical power being delivered to and/or consumed by the predetermined component (e.g., the radiation source 110) is remaining constant or substantially constant.
Because the power is constant (or substantially constant) and stable in accordance with one or more aspects of the present invention, the source may warm up slowly in one or more embodiments. Preferably, the source warms up slowly. Given the new and unique circuit designs shown in at least
As shown in
Using the new circuit design discussed herein, all the parts thereof may be very small, and less than a watt of power may be lost in the regulator. Even for the system 600 shown in
As shown in
As shown in
There are many ways to compute power, digital as well as analog. In at least one embodiment, a computer may be dedicated to the control and the monitoring of the power circuit, such as the one or more control circuits 510 and/or the power control system 600. As shown in the schematic view of
As an alternative or additional embodiment, the one or more power circuits 510 and/or the power system 600 may be digitally or substantially digitally implemented as shown in
The circuit and/or system 1500 may operate in a loop, and the loop may be closed in a number of ways. A suitable DAC command value 1575 may first be generated from the output of the digital multiplier 1570 using a digital product 1578 and the processing step 1581. This causes DAC 1585 to provide a feedback input 1584 to the power stage 1590, which also may receive a desired, commanded power input 1589 from a commanded power value 1587. The commanded power input 1589 may be a reference value that properly scaled feedback input 1584 must meet when the loop is closed. Additionally or alternatively, the commanded power input 1589 may be the actual desired power level to be delivered to the controlled or predetermined component 1501 (e.g., such as an IR source; the radiation source 110; etc.). Power stage 1590, which is capable of the full, requisite power level required by component 1501, then acts to provide the commanded power to component 1501.
The loop may also be closed using the computer 1580, which acts via the processing step 1581. The computer 1580 uses the output (also referred to as the digital product) 1578 of the digital multiplier 1570 and the commanded power value 1587 to compute the DAC command 1575 by the processing step 1581. The DAC command 1575 then controls the power stage 1590 via the output 1584 of the DAC 1585, thereby causing commanded power to be provided to component 1501.
It will be appreciated that the power stage 1590 may have many forms. Regardless of the form, the power stage 1590 operates to control at least one of the current, the voltage, and the product of current and voltage delivered to the predetermined component 1501 (e.g., such as an IR source; the radiation source 110; etc.), these values being derived, in the closed loop operation, from the commanded power 1587, and the digitally measured and multiplied values of the actual current and voltage employed by the predetermined component 1501 (e.g., such as an IR source; the radiation source 110; etc.). As a concrete example, a suitably scaled analog output (e.g., the output 1584) of a DAC circuit (e.g., DAC 1585), the value of the output having been computed by the computer 1580, may be wired directly to the aforementioned MAX15041, which may operate as the power stage 1590 in one or more embodiments of the circuit and/or system 1500. The digital multiplier 1570, used with inputs (i.e., input into the multiplier 1570) from the ADCs 1550 and 1560 (i.e., output from the ADCs 1550 and 1560), and suitably scaled in the processing step 1581, may form the input 1575 to the DAC 1585, which then generates the output 1584. In this way, the aforementioned second integrated circuit 512 (e.g., an analog multiplier MAX 4210 or some other similar circuit as described herein) may be replaced by the digital implementation disclosed herein.
Such improvement of power delivery and minimization and/or reduction of power loss as discussed herein is important for precision instrumentation applications. Indeed, as one example of such precision instrumentation application as best seen in the diagram view shown in
Turning to the details of
Any methods of the present invention, such as the methods for using the power control circuit and/or system, may be stored on a computer-readable storage medium. A computer-readable storage medium used commonly, such as, but not limited to, a hard disk, a flash memory, a CD, a DRAM or the like, an optional combination thereof, a server/database, etc. may be used to cause a processor, such as, the processors 1103, 1104 of the aforementioned computer system 1101 to perform the steps of the methods disclosed herein. The computer-readable storage medium may be a non-transitory computer-readable medium, and/or the computer-readable medium may comprise all computer-readable media, with the sole exception being a transitory, propagating signal. The computer-readable storage medium may include media that store information for predetermined or limited or short period(s) of time and/or only in the presence of power, such as, but not limited to Random Access Memory (RAM), register memory, processor cache(s), etc.
In accordance with at least one aspect of the present invention, the methods, systems, and computer-readable storage mediums related to the processors, such as, but not limited to, the processor of the aforementioned computer, etc., as described above may be achieved utilizing suitable hardware, such as that illustrated in the figures. Functionality of the invention may be achieved utilizing suitable hardware, such as that illustrated in
The present invention and/or one or more components thereof, and/or methods of using same, also may be used in conjunction with any suitable optical assembly including, but not limited to, optical assembly structures, interferometers, and/or retroreflectors such as those disclosed in U.S. Pat. Nos. 5,335,111; 5,949,543; 6,141,101; 6,473,185; 6,729,735; 6,752,503; 6,786,608; 6,827,455; 6,945,661; 7,168,817; 7,995,208; 8,092,030; 8,454,176; 8,567,968 to Bleier; U.S. Pat. No. 7,268,960 to Vishnia; U.S. Pat. Nos. 8,120,853; 8,205,852 and 8,205,853 to Jacobson et al.; and U.S. application Ser. No. 13/682,801, filed on Nov. 21, 2012, U.S. application Ser. No. 13/682,857, filed on Nov. 21, 2012, (presently pending), U.S. application Ser. No. 13/682,983, filed on Nov. 21, 2012, (presently pending), U.S. application Ser. No. 13/348,723, filed on Jan. 12, 2012, (presently pending), U.S. application Ser. No. 13/560,510, filed on Jul. 27, 2012, (presently pending), U.S. application Ser. No. 13/560,583, filed on Jul. 27, 2012, (presently pending), U.S. application Ser. No. 13/036,506, filed on Feb. 28, 2011, (presently pending), U.S. application Ser. No. 13/777,267, filed on Feb. 26, 2013 (presently pending), and U.S. application Ser. No. 13/965,333, filed on Aug. 13, 2013 (presently pending), each of which patents and applications are incorporated by reference herein in their entireties. One construction for a hollow retroreflector is as disclosed in U.S. Pat. No. 3,663,084 to Morton S. Lipkins.
Although the invention herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention.
This application is a non-provisional patent application that claims the benefit of the filing date of, and priority to, U.S. Provisional Application No. 61/730,602, filed Nov. 28, 2012, the entirety of which is incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 61730602 | Nov 2012 | US |
