WO2008077104A1

WO2008077104A1 - Determination of a metric regarding a condition of interest

Info

Publication number: WO2008077104A1
Application number: PCT/US2007/088142
Authority: WO
Inventors: Ovidiu Gabriel Vlad; Lawrence Carl Spaete, Jr.; Alfred Robert Zantow
Original assignee: Embedded Control Systems
Priority date: 2006-12-19
Filing date: 2007-12-19
Publication date: 2008-06-26
Also published as: WO2008077101A1

Abstract

An optical conduit (204) directs (101) a pulse of light energy (205) from a light source (201) in a vehicle (200) to a phosphor material (202) that is exposed to an ambient condition of interest. By detecting (102) when the phosphor material begins to fluoresce in response to the pulse of light energy, the corresponding duration of time between the pulse of light energy and when the phosphor material begins to fluoresce can be used (104) to determine a metric regarding the ambient condition of interest. This can comprise, for example, the temperature of the phosphor material and hence (at least under some operating conditions) the local temperature in the vicinity of the phosphor material. This can comprise, for example, the local air temperature, the temperature of an object upon which the phosphor material is located, and so forth.

Description

DETERMINATION OF A METRIC REGARDING A CONDITION OF INTEREST

Related Application(s^')

[0001] This application claims the benefit of U.S. Provisional application number

60/870,699, filed December 19, 2007, which is incorporated by reference in its entirety herein.

Technical Field

[0002] This invention relates generally to the determination of metrics regarding conditions of interest.

Background

[0003] Ambient conditions of various kinds can be of interest to persons traveling in a vehicle and/or can comprise important input parameters to on-board systems of various kinds. For example, in an aircraft, outside air temperature can comprise such a metric. Various sensors are known in the art to facilitate the measurement (directly or indirectly) of such ambient conditions. Though often effective for the purpose intended, such prior solutions are not necessarily well suited to all needs and application settings.

[0004] As but one example in this regard, the use of light as a medium to provide power, local lighting, and an exchange of data in an aircraft has been proposed. Existing sensor technologies are not necessarily well suited to such an application setting with respect to such considerations as compatibility, cost, weight, operating requirements, and so forth.

Brief Description of the Drawings

[0005] The above needs are at least partially met through provision of the method and apparatus to facilitate using light energy to determine a metric regarding a condition of interest described in the following detailed description, particularly when studied in conjunction with the drawings, wherein: [0006] FIG. 1 comprises a flow diagram as configured in accordance with various embodiments of the invention;

[0007] FIG. 2 comprises a block diagram as configured in accordance with various embodiments of the invention;

[0008] FIG. 3 comprises a flow diagram as configured in accordance with various embodiments of the invention;

[0009] FIG. 4 comprises a flow diagram as configured in accordance with various embodiments of the invention; and

[0010] FIG. 5 comprises a block diagram as configured in accordance with various embodiments of the invention.

[0011] Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions and/or relative positioning of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of various embodiments of the present invention. Also, common but well-understood elements that are useful or necessary in a commercially feasible embodiment are often not depicted in order to facilitate a less obstructed view of these various embodiments of the present invention. It will further be appreciated that certain actions and/or steps may be described or depicted in a particular order of occurrence while those skilled in the art will understand that such specificity with respect to sequence is not actually required. It will also be understood that the terms and expressions used herein have the ordinary technical meaning as is accorded to such terms and expressions by persons skilled in the technical field as set forth above except where different specific meanings have otherwise been set forth herein.

Detailed Description

[0012] Generally speaking, pursuant to these various embodiments, at least one optical conduit can be used to direct a pulse of light energy from a light source in a vehicle to a phosphor material that is exposed to an ambient condition of interest. Another one or more optical conduits can be used to detect when the phosphor material begins to fluoresce in response to the pulse of light energy. The duration of time between directing the pulse of light energy to the phosphor material and detecting when the phosphor material begins to fluoresce in response to that pulse of light energy can then be measured and used to determine a metric regarding the ambient condition of interest.

[0013] By one approach, this pulse of light energy can comprise, solely or in substantial part, ultraviolet light if desired. Also if desired, the same optical conduit can be used for both functions noted above (that is, directing the light energy from the light source to the phosphor material and guiding the resultant fluoresce light to a corresponding sensor).

[0014] As the duration of time required by a given phosphor material to respond to a simulation of light will vary predictably as a function of ambient temperature conditions as pertain to the phosphor material, the measured duration of time can therefore be used to determine, for example, the temperature of the phosphor material and hence (at least under some operating conditions) the local temperature in the vicinity of the phosphor material. This can comprise, for example, the local air temperature, the temperature of an object upon which the phosphor material is located, and so forth.

[0015] These teachings will also accommodate directing a pulse of heating light energy from a heating light source in the vehicle to the phosphor material to thereby quickly heat the phosphor material to a higher temperature. By employing the previously described steps both before and after heating the phosphor material in this manner, one can readily calculate, for example, the speed at which cooling air is passing by the phosphor material to achieve a particular amount of cooling over a particular period of time. In an aircraft setting, this approach can serve to determine, for example, a condition of interest such as the airspeed of the vehicle.

[0016] These teachings will also further accommodate making an airspeed determination as described at each of a plurality of different locations in the vehicle. The corresponding results can then be used to determine at least one other condition of interest such as, but not limited to, cross wind speed, cross wind directionality, tail wind speed, absolute forward speed, and so forth.

[0017] By employing light in this manner, those skilled in the art will recognize and appreciate that these teachings are readily, conveniently, and economically deployed in an application setting that makes use of a distributed light network for power distribution, data networking, and/or lighting needs. These teachings are highly leverageable and are also readily scaled to accommodate a wide variety of application setting requirements and/or opportunities.

[0018] These and other benefits may become clearer upon making a thorough review and study of the following detailed description. Referring now to the drawings, and in particular to FIGS. 1 and 2, an illustrative process and corresponding apparatus that is compatible with many of these teachings will now be presented.

[0019] This process 100 provides for using 101 at least one optical conduit 204 to direct a pulse of light energy 205 from a light energy source 201 in a vehicle 200 to a phosphor material 202 that is exposed to an ambient condition of interest 203. This vehicle 200 may comprise, for example, an aircraft of choice. Those skilled in the art will recognize that other possibilities exist as well in this regard.

[0020] The light energy source 201 can be located proximal to the ambient condition of interest 203 if desired. More typically, however, it may be preferred to locate and mount the light energy source 201 within, for example, an equipment bay or the like that is located remotely (i.e., in a different compartment) from the ambient condition of interest 203. When the optical conduit 204 comprises an optical fiber (such as a glass or a plastic optical fiber as are known in the art), those skilled in the art will recognize and appreciate that the pulse of light energy 205 can be delivered to the phosphor material 202 notwithstanding a relatively significant distance between the source and target in a convenient and inexpensive manner.

[0021] These teachings will also accommodate providing two or more of these light energy sources 201. This can provide for redundant back-up capabilities and/or a greater overall instantaneous power output, as desired.

[0022] The frequency(ies) of the light energy 205 selected for use in a given application setting can vary at least with respect to the particular phosphor material 202 being employed in that application setting. As many phosphorous materials will fluoresce when exposed to ultraviolet light, by one approach, this pulse of light energy 205 can comprise, at least in part, ultraviolet light. As various phosphorous materials will fluoresce when exposed to varying frequencies of light energy, the particular frequency(ies) employed in a given setting will of course vary with the material utilized. There are, for example, known materials that will fluoresce when exposed to light energy outside the ultraviolet range. [0023] By one approach, the phosphor material 202 can comprise a coating of phosphor material on a metal disk (not shown). That metal disk or other support substrate can serve to position the phosphor material 202 to thereby expose the phosphor material 202 to the ambient condition of interest (such as, for example, temperature). This can comprise, for example, placing the disk/phosphor material in a location to be well exposed to ambient atmospheric contents and conditions. This can also comprise, for example, placing the disk/phosphor material in direct physical and thermal contact with an object whose temperature is to be assessed. The precise phosphorous material utilized can vary with the needs and/or opportunities presented by a specific application setting as will be understood by those skilled in the art.

[0024] This process 100 also provides for using 102 at least one optical conduit 207 to detect (via, for example, a light sensor 206) when the phosphor material 202 begins to fluoresce in response to the pulse of light energy 205. In particular, this optical conduit 207 can direct such resultant fluorescent light energy 208 to a light sensor 206 to thereby permit the detection of this event.

[0025] It may be noted that FIG. 2 presents only a single optical conduit 204 and 207, respectively, to convey the pulse of light energy 205 to the phosphor material 202 and the resultant fluorescent light energy 208 to the light sensor 206. By one approach, if desired, and presuming the use of appropriate light path components as exist and as are well understood by those skilled in the art, only a single optical conduit can serve both roles. It would also be possible to employ of plurality of optical fibers for either or both of these optical pathways. Such options will be well understood by those skilled in the art and require no further elaboration here.

[0026] It may also be noted that any of a wide variety of lenses, light pipes, diffusion components, and the like (not shown) could be employed, if desired, to disperse the incoming pulse of light energy over a wide portion of the phosphor material and/or to collect the emitted fluorescent light for conveyance to the light sensor. Again, such components and their manner of use will be well understood by those skilled in the art. Accordingly, for the sake of brevity and simplicity further explanation in this regard will not be provided here.

[0027] The aforementioned light sensor 206 can be located proximal to the phosphor material 202 if desired, but may also be located elsewhere in the vehicle 200 as again the fluorescent emissions 208 of the phosphor material 202 can be suitably and effectively conveyed a considerable distance by the aforementioned optical conduit(s) 207.

[0028] This process 100 then accommodates using a signal processing circuit 209 that operably couples to both the light energy source 201 and the light sensor 206 to measure a duration of time between directing the pulse of light energy 205 to the phosphor material 202 and detecting when the phosphor material 202 begins to fluoresce in response to that pulse of light energy 205. In fact, there will be a non-zero amount of time between these two events as the phosphor material 202 will not respond instantaneously to the stimuli of the pulse of light energy 205. More particularly, there will be a predictable amount of delay between these two events that is largely dependent upon the temperature of the phosphor material 202. By knowing the particular phosphor material being utilized in a given application setting, one can also know the characteristic delays for that particular material as correspond to various temperatures.

[0029] Accordingly, this process 100 will then further accommodate having this signal processing circuit 209 use 104 this determined duration of time to thereby determine a metric regarding the ambient condition of interest. In this particular embodiment and example, this can readily comprise determining the temperature of the phosphor material 202 and hence the ambient temperature (where it may be presumed that the ambient temperature is sufficiently close to the phosphor material temperature). In particular, the calculated duration of time between sourcing the pulse of light energy 205 and detecting the resultant fluorescent light energy 208 can be used with a corresponding calculation, look-up table, or the like to identify a corresponding temperature as corresponds to that duration of response latency.

[0030] In this illustrative embodiment the signal processing circuit 209 can comprise a wholly or partially programmable platform if desired. It is also possible (and possibly preferably in various operational paradigms), however, that the signal processing circuit 209 comprise a hardware-based platform such as a Field Programmable Gate Array (FPGA) or an Application Specific Integrated Circuit (ASIC). As used herein, this will be understood to refer to a signal processing platform having logic elements that are each comprised of dedicated corresponding hardware components. In particular, it will be understood that this reference to a hardware-based platform specifically refers to a processing platform that lacks executable soft-coded program instructions (where the latter are understood to comprise software-based instructions as versus hard-wired components).

[0031] So configured and arranged, those skilled in the art will recognize and appreciate that a metric regarding an ambient condition of interest can be remotely sensed based upon using only the intervening transport of light. This, in turn, permits the phosphor material 202 to be mounted essentially anywhere with respect to the vehicle 200 including both internally and externally without requiring the use of expensive and potentially troublesome electrical conductors such as copper wiring. It will also be understood and appreciated that these teachings will accommodate employing a plurality of such optically- based sensors to determine the metric of interest (either in a redundant manner or with respect to a variety of different locations of interest).

[0032] These teachings will also accommodate using the described process 100 as a component step of yet other processes to determine other conditions of interest. As an illustrative example in this regard, and referring now to FIG. 3 (and with continued reference to FIG. 2), such a process 300 will be described.

[0033] Pursuant to this process 300, the above-described process 100 then provides for using 301 at least one optical conduit 211 to direct a pulse of heating light energy 212 from a heating light source 210 in the vehicle 200 to the phosphor material 202 to thereby quickly heat the phosphor material 202 to a higher temperature (i.e., to a temperature higher than what the ambient conditions for the phosphor material 202 would otherwise ordain).

[0034] As before, this optical conduit 211 can comprise an optical fiber (comprised as desired of glass or plastic) and may in fact comprise a plurality of such fibers as may be useful to deliver a sufficient amount of heating energy to the phosphor material 202 to achieve the desired temperature rise within the desired period of time. Also as before, the heating light energy source 210 can be located proximal to the phosphor material 202 or can be located a considerable distance away as desired. For example, in many cases, optical fibers will effectively deliver a largely unattenuated light signal for distances of up to 100 meters or more (depending in some cases upon the frequency(ies) of the light energy itself). Also as before, this optical conduit 211 may be combined with any of the previously described optical conduits (204 and 207) as are also employed for other purposes. [0035] By one approach, this heating light energy source 210 is also operably coupled to the signal processing circuit 209. So configured, the functionality and activities of the former can be at least partially controlled by the latter. Also by one approach, this heating light energy source 210 can provide heating light energy in the infrared spectral range.

[0036] The instantaneous amount of heating energy delivered to the phosphor material 202, and the duration of the delivery, can vary with the needs and/or opportunities presented in a given application setting as will be well understood by those skilled in the art.

[0037] This process 300 then determines and uses 302 a first duration of time to thereby determine a first value for a metric of interest. In this example, this metric of interest comprises the temperature in the ambient vicinity 203 of the phosphor material 202.

[0038] Following a brief predetermined interval T (as denoted by reference numeral

303, which can be on the order of a few tens of milliseconds (or less or more as desired), this process 300 then provides for again using the first described process 100 at step 304 to again, in this example, determine a second value for the metric of choice (in this example, the temperature as pertains to the phosphor material 202). The signal processing circuit 209 can then use 305 these first and second determined values for the metric of choice to determine another condition of interest. For example, by positioning the phosphor material 202 in such a way as to be exposed to a flow of external air, wherein that flow is a predictable function of the speed of air flowing past the vehicle 200, the difference in temperature of the phosphor material 202 before and after the application of the heating energy can serve to determine the quantity of air that has flowed past the phosphor material 202 to influence the observed temperature results.

[0039] Numerous variations with respect to such a process can of course be accommodated. By one approach, for example, more than two such temperature readings can then be taken at given intervals to observe the cooling behaviors of the phosphor material 202 via a greater number of data points. The latter, in turn, can serve to make a more accurate determination regarding, in this example, airspeed of the vehicle 200.

[0040] Just as the first described process 100 can be implemented more than once in service of another process 300, the second described process 300 can itself be implemented a plurality of times in order to facilitate the development of a metric for yet another condition of interest. To illustrate, and referring now to FIGS. 4 and 5, a corresponding process 400 can provide for determining 401 a condition of interest (such as, in the example given above, airspeed) for each of a plurality of different locations on the vehicle 200. In this illustrative example, these multiple locations are denoted as a first location 203 through an Nth location 501, where N will be understood to comprise an integer greater than one. These locations can correspond, for example, to locations where airspeed as sensed with respect to various directions can be sensed and assessed. In such a case, the signal processing circuit 209 can then process and use 402 the corresponding results for each of these different locations to determine at least one other condition of interest.

[0041] When the corresponding results each comprise an airspeed value, this step of using these results can comprise using these airspeed values from different locations on the vehicle 200 to determine one or more of cross wind speed, cross wind directionality, tail wind speed, absolute forward speed, and so forth. As the described optically-based sensors are each relatively simple and potentially quite small in size, and further as these sensors are also each likely to be quite relatively inexpensive, these optically-based sensors can be deployed in a relatively generous manner to thereby facilitate the ready determination of a wide variety of such conditions of interest.

[0042] Those skilled in the art will recognize that a wide variety of modifications, alterations, and combinations can be made with respect to the above described embodiments without departing from the spirit and scope of the invention, and that such modifications, alterations, and combinations are to be viewed as being within the ambit of the inventive concept.

Claims

We claim:

1. A method comprising: using at least one optical conduit to direct a pulse of light energy from a light source in a vehicle to a phosphor material that is exposed to an ambient condition of interest; using at least one optical conduit to detect when the phosphor material begins to fluoresce in response to the pulse of light energy; measuring a duration of time between directing the pulse of light energy to the phosphor material and detecting when the phosphor material begins to fluoresce in response to the pulse of light energy; using the duration of time to determine a metric regarding the ambient condition of interest.

2. The method of claim 1 wherein the vehicle comprises an aircraft.

3. The method of claim 1 wherein a same optical conduit is used to direct the pulse of light energy to the phosphor material as is used to detect when the phosphor material begins to fluoresce.

4. The method of claim 3 wherein the optical conduit comprises a plastic optical fiber.

5. The method of claim 1 wherein the ambient condition of interest comprises air temperature.

6. The method of claim 1 further comprising using the metric regarding the ambient condition of interest to determine a condition of interest.

7. The method of claim 6 wherein the condition of interest comprises air speed of the vehicle.

8. The method of claim 7 further comprising: using at least one optical conduit to direct a pulse of heating light energy from a heating light source in the vehicle to the phosphor material to thereby quickly heat the phosphor material to a higher temperature.

9. The method of claim 8 wherein: using at least one optical conduit to direct a pulse of light energy from a light source in a vehicle to a phosphor material comprises directing a first pulse of light energy to the phosphor material prior to directing the pulse of healing light energy to the phosphor material and directing a second pulse of light energy to the phosphor material subsequent to directing the pulse of heating light energy to the phosphor material; using at least one optical conduit to detect when the phosphor material begins to fluoresce comprises detecting a first time when the phosphor material begins to fluoresce in response to the first pulse of light energy and a second time when the phosphor material begins to fluoresce in response to the second pulse of light energy; measuring a duration of time between directing the pulse of light energy to the phosphor material and detecting when the phosphor material begins to fluoresce in response to the pulse of light energy comprises, measuring a first duration of time between directing the first pulse of light energy to the phosphor material and detecting the first time when the phosphor material begins to fluoresce in response to the pulse of light energy and measuring a second duration of time between directing the second pulse of light energy to the phosphor material and detecting the second time when the phosphor material begins to fluoresce in response to the pulse of light energy; using the duration of time comprises: using the first duration of time to determine a first temperature and the second duration of time to determine a second temperature; using the first temperature and the second temperature to determine the airspeed of the vehicle.

10. The method of claim 9 further comprising: processing the described steps for each of a plurality of different locations on the vehicle and using the corresponding results to determine at least one other condition of interest.

11. The method of claim 10 wherein the at least one other condition of interest comprises at least one of: cross wind speed; cross wind directionality; tail wind speed; absolute forward speed.

12. The method of claim 1 wherein the light energy comprises ultraviolet light energy.

13. An apparatus comprising: a source of light energy mounted within a vehicle that is configured and arranged to output a pulse of light energy; a phosphor material that is exposed to an ambient condition of interest; a light sensor; at least one optical conduit operably coupled between the source of light energy and the phosphor material; at least one optical conduit operably coupled between the phosphor material and the light sensor; a signal processing circuit operably coupled to at least the light sensor and being configured and arranged to: determine via the light sensor when the phosphor material begins to fluoresce in response to the pulse of light energy; measure a duration of time between a sourcing of the pulse of light energy to the phosphor material and when the phosphor material begins to fluoresce in response to the pulse of light energy; use the duration of time to determine a metric regarding the ambient condition of interest.

14. The apparatus of claim 13 wherein the vehicle comprises an aircraft.

15. The apparatus of claim 13 wherein the optical conduits comprise plastic optical fibers.

16. The apparatus of claim 13 wherein the ambient condition of interest comprises air temperature.

17. The apparatus of claim 13 wherein the signal processing circuit is further configured and arranged to use the metric regarding the ambient condition of interest to determine a condition of interest.

18. The apparatus of claim 17 wherein the condition of interest comprises air speed of the vehicle.

19. The apparatus of claim 18 further comprising: a source of heating light energy that is configured and arranged to output a pulse of heating light energy; at least one optical conduit operably coupled between the source of heating light energy and the phosphor material; such that heating light energy from the source of heating light energy can selectively quickly heat the phosphor material.

20. The apparatus of claim 19 wherein the signal processing circuit is further configured and arranged to: measure a duration of time between a sourcing of the pulse of light energy to the phosphor material and when the phosphor material begins to fluoresce in response to the pulse of light energy by: measuring a first duration of time between a sourcing of a first pulse of light energy to the phosphor material, which first pulse of light energy is applied subsequent to the pulse of heating light energy, and when the phosphor material begins to fluoresce in response to the first pulse of light energy; and measuring a second duration of time between a sourcing of a second pulse of light energy to the phosphor material, which second pulse of light energy is applied subsequent to the pulse of heating light energy, and when the phosphor material begins to fluoresce in response to the second pulse of light energy; use the duration of time by: using the first duration of time to determine a first temperature and the second duration of time to determine a second temperature; using the first temperature and the second temperature to determine the airspeed of the vehicle.

21. The apparatus of claim 20 wherein the signal processing circuit is further configured and arranged to determine airspeed information at a variety of locations on the vehicle to thereby determine at least one other condition of interest.

22. The apparatus of claim 21 wherein the at least one other condition of interest comprises at least one of: cross wind speed; cross wind directionality; tail wind speed; absolute forward speed.