OPTICAL SENSOR DEVICE

Abstract

An optical sensing system is presented for monitoring one or more parameters or conditions of an object. The optical sensing system comprises: an elongated light guide configured for placing in proximity of the object, the light guide defining a cavity for light propagation therethrough along at least one light propagation path, and having a light input port and at least one light output port; and a detector system for receiving light propagating from the at least one light output port, the detector system being configured and operable for monitoring a signal modulated by light interaction with the object and being indicative of the at least one parameter/condition of the object.

Claims

1. An optical sensing system for monitoring one or more parameters or conditions of an object, the optical sensing system comprising: an optical sensor unit comprising at least one elongated light guide configured for placing in proximity of the object, the light guide defining a cavity for light propagation therethrough along a light propagation path, and having a light input port and at least one light output port; and a detector system for receiving light propagating from the at least one light output port, the detector system being configured and operable for monitoring a signal modulated by light interaction with the object and being indicative of the at least one parameter/condition of the object.

2. The optical sensing system according to claim 1, wherein the detector system is configured as an interferometric detector system adapted for monitoring an interference signal resulting from interference between light modulated by the interaction with the object and non-modulated light, the interference signal being indicative of the at least one parameter of the object.

3. The optical sensing system according to claim 2, wherein the non-modulated light is light propagating along a reference path in the interferometric detector system outside the light guide.

4. The optical sensing system according to claim 2, wherein the interference signal is indicative of self-interference between the modulated and non-modulated light components propagating in said cavity and being reflected from different locations along the light guide being respectively affected and non-affected by an external signal originated at the object.

5. The optical sensing system of any one of the preceding claims, wherein the signal modulated by the light interaction with the object is indicative of motion originated at the object, thereby enabling monitoring acoustic signals corresponding to the motion originated at the object.

6. The optical sensing system according to claim 1, wherein the light guide as at least one of the following configurations: (i) the light guide comprises one or more interacting ports located in said cavity downstream of the input port of the light guide with respect to a direction of propagation of the input light, the interacting port being configured to allow light propagating in the light guide to emerge from the light guide towards the object and receive light returned from the object and being modulated by direct interaction with the object; (ii) the light guide comprises one or more light redirecting elements located in one or more locations, respectively, in the cavity defined by the light guide and adapted for directing light, propagating in said cavity, towards the one or more output ports; (iii) the light guide is substantially flexible allowing its placing in contact with and along a portion of the object; (iv) the light guide comprises at least one optical fiber.

7-8. (canceled)

9. The optical sensing system of claim 1, wherein the light guide is substantially flexible allowing its placing in contact with and along a portion of the object, interaction between the flexible light guide and the portion of the object causes deformation of the light guide according to a motion originated at the object, thereby modulating light propagating along said path, such that a light modulation pattern is indicative of a deformation pattern of the light guide which corresponds to a motion pattern of the object.

10. (canceled)

11. The optical sensing system of claim 1, wherein the light guide comprises at least one optical fiber, the optical fiber being formed with one or more scattering points arranged in one or more locations a core of the fiber, the one or more scattering points directing light propagating in the fiber towards the one or more output ports of the fiber.

12. The optical sensing system of claim 1, wherein the detection system comprises a communication utility adapted for data communication with a control unit, which is adapted for processing and analyzing the signal modulated by the light interaction with the object and determining said one or more parameters of the object.

13. (canceled)

14. The optical sensing system of claim 1, further comprising a light source unit for producing input light and directing the produced light into the light guide via the input port thereof.

15. The optical sensing system of claim 14, wherein the light source unit has at least one of the following configurations: (1) the light source unit is configured and operable for producing the input light having light components of different wavelengths; and (2) the light source unit is configured and operable for producing light of predetermined polarization state.

16-19. (canceled)

20. The optical sensing system claim 1, having at least one of the following configurations: (a) the input and output ports are associated with the same end of the elongated light guide; (b) the input and output ports are associated with opposite ends of the elongated light guide.

21. (canceled)

22. The optical sensing system of claim 1, wherein the optical sensor unit comprises at least one additional light guide having a light input port and at least one light output port, said detector system comprising at least two detectors associated with the at least two light guides respectively, each of the at least two detectors receiving light output from the respective light guide and generating measured data indicative of light interaction with the object at a location of the respective light guide, the detection system being configured for communication with a control unit adapted for processing and analyzing the measured data and determining said one or more parameters of the object.

23. (canceled)

24. An optical sensor device for use in a sensing system for monitoring one or more parameters or conditions of an object, the device comprising: a light guide unit comprising at least one elongated light guide configured for placing in proximity of an object to be monitored, the light guide defining a cavity for light propagation therethrough along a light propagation path, and having a light input port for inputting light to propagate along said path, and at least one output port associated with a detection system, said elongated light guide having at least one of the following configurations: (i) the at least one light guide comprises one or more interacting ports located downstream of the input port, the interacting port being configured to allow light to emerge from the light guide towards the object and receive light returned from the object and being modulated by a modulation pattern indicative of interaction of light with the object, said modulation pattern corresponding to a motion pattern originated at the object, being indicative of at least one parameter or condition of the object; and (ii) the at least one light guide is substantially flexible allowing its placing in contact with and along a portion of the object, such that interaction between the flexible light guide and the portion of the object causes deformation of the light guide according to a motion originated at the object, thereby modulating light propagating along said path, such that a light modulation pattern is indicative of a deformation pattern of the light guide which corresponds to a motion pattern originated at the object being indicative of at least one parameter or condition of the object.

25-26. (canceled)

27. The optical sensor device of claim 24, comprising an interferometric detector located at said at least one output of the light guide for detecting an interference signal resulting from interference between the light modulated by the interaction with the object and non-modulated light, the interference signal being indicative of the at least one parameter or condition of the object.

28. The optical sensor device of claim 27, wherein the non-modulated light is light propagating along a reference path in the interferometric detector outside the light guide.

29. The optical sensor device of claim 27, wherein the interference signal is indicative of self-interference between the modulated and non-modulated light components propagating in said cavity and being reflected from different locations along the light guide being respectively affected and non-affected by an external signal originated at the object.

30. The optical sensor device of claim 24, wherein the light guide has one of the following configurations: (i) the light guide comprises light directing elements located in a spaced-apart arrangement in the cavity defined by the light guide and adapted for direct light, propagating in said cavity, towards the at least one output port; (ii) the light guide comprises at least one optical fiber, the optical fiber being formed with an array of scattering points arranged in spaced-apart relationship along a core of the fiber, said scattering points directing light propagating in the fiber towards the at least one output port.

31. (canceled)

32. The optical sensor device of claim 24, having at least one of the following configurations: (1) the input and output ports are associated with the same end of the elongated light guide; (2) the input and output ports are associated with opposite ends of the elongated light guide.

33-34. (canceled)

35. The optical sensor device of claim 24, wherein the light guide unit comprises at least one additional light guide having a light input port and at least one light output port.

36. A fabric material carrying the optical sensor system of claim 1, being integral with or embedded in the fabric material.

37. A fabric material carrying the optical sensor device of claim 24, being integral with the fabric material.

38. The fabric material of claim 36, configured to be worn by an individual for carrying out one or more of the following: non-contact bio monitoring of one or more parameters of the individual comprising at least one of the following: breathing, heart beating, blood pulse pressure, pulse oximetry related parameters, lactate concentration, blood flow velocity, blood volume; and recording acoustic signals indicative of conversations performed by the individual in a range of up to a few meters from the fabric material.

39. A fabric material of claim 37, configured to be worn by an individual for carrying out one or more of the following: non-contact bio monitoring of one or more parameters of the individual comprising at least one of the following: breathing, heart beating, blood pulse pressure, pulse oximetry related parameters, lactate concentration, blood flow velocity, blood volume; recording acoustic signals indicative of conversations performed by the individual in a range of up to a few meters from the fabric material.

40. (canceled)

41. The fabric material of claim 36, wherein the optical sensor device comprises a plurality of at least two of the light guides located in a spaced apart relationship such that when the fabric material is warned by an individual, the at least two light guides are positioned in different spatial locations along the same blood artery.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to better understand the subject matter that is disclosed herein and to exemplify how it may be carried out in practice, embodiments will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which:

[0034] FIG. 1 is a block diagram of an optical sensing system of the invention;

[0035] FIGS. 2A and 2B are schematic illustrations of the configuration and operation of an optical sensing system according to some embodiments of the invention;

[0036] FIGS. 3A to 3D illustrate a specific example of the optical sensing system of the invention, where FIG. 3A shows a basic optical setup, FIG. 3B shows a snapshot of the basic experimental system; and FIGS. 3C and 3D present two alternatives for usage/integration of the fiber based optical sensor into the fabric; and

[0037] FIGS. 4A to 4C illustrate experimental results for bio-medical non-contact fiber based sensing system of the invention, where FIG. 4A shows a periodic signal of heart beats taken from T-Shirt with fiber based sensor, FIG. 4B shows extraction of breathing recorded via the fiber positioned near the chest of a subject, and FIG. 4C shows sound extracted with the fiber-microphone installation.

DETAILED DESCRIPTION OF EMBODIMENTS

[0038] The present invention provides a novel optical sensor device and a sensing system using the same, in which one or more parameters of an object (e.g. subject's body) are determined based on monitoring light propagation through a light guide located in the proximity of the object (close proximity or in physical contact with the object), such that the detected light is indicative of/modulated by interaction between the object and either the light from the light guide or the light guide itself. In other words, the modulation of the detected light is a result of either direct interaction between the light and object, or via deformation of the light guide (change of the optical path of light in the light guide) as a result of direct interaction between the light guide and object.

[0039] The optical sensor device of the invention includes an elongated light guide (e.g. optical fiber) defining a path for light propagation therethrough, and having a light input port for receiving input light from a light source (e.g. laser), and a light output port where light is collected towards a detector system. The light input and output ports may be at the same or opposite ends of the light guide.

[0040] Thus, in some embodiments of the invention, a fiber is used as a light guide, which can be a plastic fiber rather than glass one (e.g. to make it more flexible when integrated into a fabric). In some embodiments, light redirecting elements (at times termed here “scattering points”) may be provided in the fiber core arranged in a spaced-apart relationship along the axial dimension, i.e. along the light propagation path. In the embodiments where the light input and the light output ports are associated with the same location (end portion) of the fiber, the scattering points may be used to cause the light to be back reflected to propagate back towards the input/output end of the fiber, which in some embodiments may also be used for monitoring the self-interference between these light components. Alternatively or additionally, the scattering points may be used as interaction ports to cause light to exit the fiber, interact with the nearby tissue and be back reflected from it and coupled back into the fiber. The scattering points may be discontinuity points along the core (cavity of light propagation) of the elongated light guide. The discontinuity may be due to change in the real or imaginary parts of the refraction index of the light guiding core.

[0041] The light that is back reflected is detected, e.g. via interference with the injected (input) light beam, and used to extract temporal changes in the detected light. Generally, the inventors have shown that temporal changes in the detected light, corresponding to light modulation by interaction with an object being monitored (direct interaction or via deformation of the light guide), can be used as a “microphone” at proximity of the object, e.g. embedded into the fabric, or as an embedded biomedical/biometric sensor. The inventors have experimentally demonstrated the capability of the optical sensing system to “hear” sound (voices), as well as to sense heart beating and breathing, without having full contact between the fiber and the measured subject. The fiber sensors can be incorporated into the fabric (shirt, sheets, shoes etc) and used for biomechanical sensing (breathing of babies when incorporated into sheets), biomedical monitoring for subjects (heart beats), biochemical monitoring for subjects (for instance, alcohol level in blood). The fabricated fibers can be thinner than the fibers used for optic communication (since for the purposes of the invention there is no need to conduct light for distances of hundreds of kilometers) and can be as thin as only few tens of microns.

[0042] FIG. 1 schematically illustrates, by way of a block diagram, an optical sensing system 10 of the invention for monitoring one or more parameters/conditions of an object 30. The optical sensing system 10 includes an optical sensor device 11 (a so-called “fiber part” of the system 10) formed by an elongated light guide 12 configured for placing in proximity of an object to be monitored, and an electronic unit 15 (a so-called “connector” part of the system 10). The light guide unit 12 defines at least one cavity 17 for light propagation therethrough along at least one light propagation path. Generally speaking, the light guide unit 12 includes one or more light guides (at times referred to as light guiding elements) each defining a light propagation path. The light guide has a light input port 12A and one or more light output ports 12B. In this schematic illustration, the light input and output ports 12A and 12B are exemplified as being associated with opposite ends of the light guide. It should, however, be understood, and will also be exemplified further below, that the invention is not limited to this configuration.

[0043] In some embodiments, the optical sensor device 11 may also include one or more interaction ports, generally at 20, located inside the light guide downstream of the input port 12A. The interaction port 20 is actually a light input/output port configured to allow light propagating in the cavity 17 of the light guide 12 to emerge from the light guide towards the object 30 and receive and light returned from the object 30 and being modulated by direct interaction with the object. The provision of the interaction port(s) is optional, and is used in the device configuration utilizing direct interaction between the light and object.

[0044] In some embodiments, the optical sensor device 10 also includes one or more internal light redirecting elements, generally at 14, located inside the light guide and being arranged in a spaced-apart relationship along the light propagation path. The light redirecting elements 14 reflect/deflect light propagating inside the cavity towards the light output 12B.

[0045] The electronic unit 15 includes a control unit (processor unit) 22 and a power supply unit (battery) 23, and may also include or be connectable to a light source/transmitter unit 16 and a detector system 18. As shown, light from the light source 16 is input to the light guide 12 via the light input port 12A, and light is collected at the output port 12B to be received by the detector system 18, either directly by locating the detector at the light output port 12B or via suitable light directing element(s) such a light guide, mirror(s), etc.

[0046] The light source unit 22 may be configured for producing single- or multi-wavelength input light, and/or light polarized light. The detection system is configured and operable for receiving output light and generating measured data indicative thereof. As will be described more specifically further below, the detected light is indicative of (modulated by) light interaction with the object. The control unit 22 is configured for receiving measured data and processing it to identify the modulation and determine one or more parameters/conditions of the object.

[0047] As further schematically shown in FIG. 1, in some embodiments, the light guide unit 12 may include at least one additional light guide 12′ having input and output ports 12A′ and 12B′. The two light guides 12 and 12′ may be configured generally similar to one another, and are associated with the same or different detector units at the detection system 18. The multiple (at least two) measured data pieces obtained from the light output of the light guides, respectively, are processed by the control unit 22. The at least two light guides may be used for measurement of the same or different parameters/conditions of the object.

[0048] For example, the system may be configured for measuring the individual's blood flow velocity and volume, using the light guide sensor carried by a fabric warned by the individual. The two light guides (fibers) 12 and 12′ are positioned such that they intersect the blood artery axis BA and are spaced from one another a certain distance d. The light input ports 12A and 12A′ of the fibers receive input light from the same light source unit (or separate light source units, as the case may be), and light output ports 12B and 12B′ of two fibers 12 and 12′ are associated with/connected to separate interferometric detector at the detection system 18. Two measured data pieces MD and MD′, indicative of light interaction with the body at different locations L and L′ respectively, are thus provided and processed by the control unit 22. The control unit 22 is configured for processing and analyzing the measured data pieces and determining the time that the same heart beat progresses the distance d from one fiber (location L) to the other fiber (location L′), and extracting the arriving modulated signal to each one of these locations, to determine the blood flow velocity and volume.

[0049] The following are some specific but not limiting examples of the configuration and operation of the optical sensing system of the invention. To facilitate illustration and understanding, the same reference numbers are used for identifying components that are common in all the examples.

[0050] FIGS. 2A and 2B show schematically an optical sensing system 10 according to somewhat different examples of the invention adapted for monitoring one or more parameters or conditions of an object. The optical sensing system 10 includes an optical sensor device 12 including an elongated light guide 12 defining a cavity 17 for light propagation therethrough along the light guide (light propagation path), and having a light input port 12A at one end of the light guide, and one or more light output ports 12B.

[0051] In the present examples, the light guide 12 is an optical fiber caving a core 31 and cladding 33. Also, in the present not limiting examples of FIGS. 2A and 2B, the light output port 12B is located at the same end of the light guide as the input port 12A. In the example of FIG. 2B, the light detection system is configured as an interferometric light detector.

[0052] As shown, input light L.sub.1 is injected from a light source/transmitter unit 16 into the light guide 12 at the light input 12A, e.g. via beam splitter 27 (the provision of which is optional), and propagates through the light guide cavity 17 along the light propagation path in the forward direction (input light propagation direction). In some embodiments, e.g. those where the detector-related light output and the light input are located at the same end of the light guide, the light guide is formed with light redirecting elements 14 arranged in a spaced-apart relationship along the light propagation path. The light redirecting elements may be implemented as scattering points in a fiber (e.g. specifically introduced defects), which reflect input light L.sub.1 to cause reflected light L.sub.2 to propagate back along said path towards the light output 12B, where it is collected and directed (e.g. via beam splitter 27) to the detector unit 18 (interferometric detector system in the example of FIG. 2B).

[0053] Generally, the detector system 18 may be of any known suitable configuration, being operable for continuously detecting light output from the light guide 12 during a predetermined time interval (measurement session), and generating output data in the form of a time function of the detected light. The detected light is modulated by interaction of light with the object. As indicated above, this may be direct interaction, or interaction via deformation of the light guide due to the motion originated in the object.

[0054] Considering the example of FIG. 2A, the modulation of the detected light may be amplitude modulation, which may be a direct measure of the motion pattern, and/or the modulation may be indicative of a change of polarization state of light, i.e. a so-called “polarization sensing”. In the latter case, light L.sub.1 injected in the light guide 12 may be polarized light, and the system may include polarizers at the illumination path (input light propagation from the light source to the light input port 12A) and a detection path (light propagation path from the light output 12B to the detector system).

[0055] In the example of FIG. 2B, the interferometric detector system 18 is used which may have any known suitable configuration. In some embodiments, detected combined light L.sub.3 is formed by output light L.sub.2 (modulated by interaction with the object/tissue) interfering with a reference beam L.sub.ref whose propagation path is varied using a mirror 29. In some other embodiments combined light L.sub.3 is a result of interference between different components of the output light L.sub.2, which are reflected from different locations along the light guide 12 such that they include light components modulated by interaction with a region of interest in the tissue (object) and non-modulated light components.

[0056] It should be understood that each of FIGS. 2A and 2B actually illustrates two examples of the invention, which may be implemented separately or in combination.

[0057] According to one example, there are no other light outputs in the light guide, other than light output port 12B where the output light is collected to the detector, and the interaction between light and tissue is via the flexible light guide 12. More specifically, due to the movement of the tissue (or, generally, motion/vibration originated at the tissue), the flexible light guide 12, being in physical contact with the tissue along its length or at least part thereof, deforms such that a deformation pattern of the light guide corresponds to the motion pattern of the tissue. The deformation of the light guide (cavity 17) results in the respective deformation of the light path in the cavity, i.e. trajectory of light L.sub.2, and accordingly induces a modulation pattern, corresponding to the tissue motion. This modulation is identified in the detected signal/measured data (e.g. interference signal) at the detector system.

[0058] According to the other example shown in each of FIGS. 2A and 2B, the light guide 12 (which may not be flexible) is located in the close proximity of the tissue, and is formed with additional light output ports, i.e. interaction ports 20, arranged in a spaced-apart relationship along the light guide. Input light L.sub.1 (and possibly also output light L.sub.2 deflected by redirecting elements 14) propagates through the light guide 12, and portions L.sub.4 thereof emerge from the light guide 12 through the interaction ports 20, interact with the tissue and return back into the light guide (e.g. using additional external re-directing elements on the outer surface of the light guide, which are not specifically shown). These light portions L.sub.4 are therefore modulated by direct interactions with the tissue, and this modulation pattern corresponds to the tissue motion pattern.

[0059] As further shown in the figures, the optical sensing system 10 is associated with the electronic unit 15 including a control unit 22, which is connectable (via wires or wireless signal transmission of any known suitable type) with the detector system 18 for receiving and analyzing the detected signals (measured data) to determine one or more parameters of the tissue from the identified motion pattern originated in the tissue.

[0060] As further shown in the figures, in some embodiments, the control unit 22 may be appropriately connectable with the light source unit 16 and adapted to modulate the input light L.sub.1, e.g. induce spectral modulation. Also, as described above, at least the fiber part 12 (optical sensor device), or both the fiber part 12 and the connector part 15 (electronic unit) may be configured to be disposable.

[0061] Reference is now made to FIGS. 3A-3D which illustrate a specific example of the optical sensing system of the invention. FIG. 3B shows in a self-explanatory manner a snapshot of the basic experimental system. FIG. 3A shows more specifically the configuration and operation of basic optical setup, including an optical sensor device 12 configured as described above according to either one or combination of the above-described embodiments, a transmitter (light source) 16, and a detector 18 (e.g. an interferometric detector). In this example the light guide sensor 12 (e.g. fiber based) extends between the transmitter 16 and detector 18, along the tissue being monitored, while being in the proximity of the tissue (thus including interaction ports 20) or in physical contact with the tissue (thus either including the interaction ports 20 or not). As also shown in the figure, the detector system 18 is in wireless communication with an external electronic device 15, such as phone device. Such electronic device 15 may be installed with data processor utility (control unit 22) for processing the detected signal, or, as shown in the figure in dashed lines, the phone device may be used just for transmitting the signal received from a stand-alone control unit 22 to a remote control station (server) 37 via a communication network, or a so-called “distributed data processing” may be used, e.g. the electronic device performs the initial processing and selectively forwarding data to the central station only upon identifying a certain degree of abnormality in the detected parameter/condition of the tissue.

[0062] FIGS. 3C and 3D present two alternatives for usage/integration of the fiber based optical sensor 12 into the fabric, utilizing partially and full integration of the system. In both examples, the optical sensing system 10 includes an optical sensor device (fiber-part 12) formed by multiple fibers (light guides), and a connector part 15 including an electronic system. The fiber-part 12 of the system is fully embedded in a fabric 40.

[0063] As for the electronic system 15, in some embodiments exemplified in FIG. 3D, it may be also fully integrated in the fabric 40, and may be operable (actuated) from a remote station via a communication utility 35 in the embedded electronic system 15. In such fully-embedded optical sensing system 10 exemplified in FIG. 3D, it includes the fiber sensor 12 and the electronic system 15 including a detection system 18, a light source unit 16; a power supply (battery) 23, and a communication utility 35, and may or may not include the processor (22 in FIG. 1) and may communicate either the processing results to an external control station/storage device or may communicate raw data (measured data) to an external control station to be processed and stored there.

[0064] As exemplified in FIG. 3C, the optical sensing system may include an embedded part and an external part. The embedded part may include the fiber part (fiber sensor) 12 and a part of the electronic system 15 including a light source 16, a poser supply 23, and a communication utility 35; and the external part includes a corresponding communication utility 37, detector 18 and energy source 23. Similarly, the system may include the processor 22 located in its external part and connected to the output of the detector and operable to communicate the processing results to an external control station/storage device, or may be configured for communicating with the processor located at the external control station. As indicated above, the software modules of the control unit/processor may be distributed between the embedded and external parts of the electronic system.

[0065] Preliminary experimental results for bio-medical non-contact fiber based sensing can be seen in FIGS. 4A-4C. For instance FIG. 4A shows the non-contact extraction of heart beating which yields typical beating rate of 1.12 Hz and it exactly matches the reference measurement of 67 bpm measured with electric Mio watch. FIG. 4B shows extraction of breathing, and FIG. 4C shows that the invention can also be used as a microphone that can record the voice of the speaker or the sounds around him.