OPTICAL SENSOR CONTAINING A WAVEGUIDE WITH HOLOGRAPHIC ELEMENTS FOR MEASURING A PULSE AND BLOOD OXYGEN SATURATION

Abstract

A spectrometry device includes a carrier medium, or waveguide, for transmitting light by internal reflection, and a transceiver device that has at least one light source and a detection device. A transceiver deflection structure couples at least the light emitted by the light source into the carrier medium. A measurement deflection structure, arranged at a distance from the transceiver deflection structure, decouples the light out of the carrier medium onto a measuring surface of the carrier medium so that the biological tissue can reflect the light back to the carrier medium. The reflected light is transmitted back onto the detection device via the measurement deflection structure, the carrier medium and the transceiver deflection structure. The detection device determines an intensity signal of the reflected light which is used by an analysis device to determine a pulse frequency signal and/or a pulse curve signal as a medical characteristic value.

Claims

1-10. (canceled)

11. A spectrometry device for noninvasive measurement of at least one medical characteristic value on biological tissue, comprising: a carrier medium, formed as a light guide for transmitting coupled-in light by internal reflection, having a transceiver region and a measuring region arranged offset along a longitudinal extension direction of the carrier medium with respect to the transceiver region and provided for application of the biological tissue; and a transceiver device having a detection device and at least one first light source to emit first light having a first wavelength onto the transceiver region of the carrier medium, the transceiver region having a predefined transceiver deflection structure to couple at least the first light emitted by the first light source into the carrier medium towards the measuring region, the measuring region having a predefined measuring deflection structure configured to decouple the first light out of the carrier medium towards a measuring surface of the carrier medium in the measuring region, the biological tissue reflecting the first light back to the carrier medium when the biological tissue is applied to the measuring surface, and couple the first light reflected from the biological tissue back into the carrier medium towards the predefined transceiver deflection structure of the transceiver region where the first light is decoupled out of the carrier medium onto the detection device of the transceiver device, and the detection device, configured to determine a first intensity signal of the first wavelength; having an evaluation unit configured to determine at least one of a pulse frequency signal and a pulse curve signal as a medical characteristic value based on a time curve of the first intensity signal.

12. The spectrometry device as claimed in claim 11, wherein the first wavelength is in a range from 600 nm to 800 nm.

13. The spectrometry device as claimed in claim 12, wherein the first wavelength is 660 nm.

14. The spectrometry device as claimed in claim 12, wherein the transceiver device further comprises a second light source to emit second light having a second wavelength onto the transceiver region of the carrier medium, wherein the predefined transceiver deflection structure of the transceiver region is configured to couple the second light emitted by the second light source into the carrier medium towards the measuring region, wherein the detection device is configured to determine a second intensity signal of the second wavelength, and wherein the evaluation unit is configured to determine a blood oxygen saturation as a medical characteristic value from the first intensity signal and the second intensity signal.

15. The spectrometry device as claimed in claim 14, wherein the second wavelength is in a range of 850 nm to 1000 nm.

16. The spectrometry device as claimed in claim 15, wherein the second wavelength is 940 nm.

17. The spectrometry device as claimed in claim 15, wherein the detection device is configured to distinguish between the first wavelength and the second wavelength.

18. The spectrometry device as claimed in claim 17, further comprising a housing configured to protect the transceiver region and the transceiver device from outside light.

19. The spectrometry device as claimed in claim 18, wherein each of the predefined transceiver deflection structure and the predefined measuring deflection structure have at least one optical grating.

20. The spectrometry device as claimed in claim 19, wherein the at least one optical grating is one of a surface holographic grating and a volume holographic grating having a multiplex diffraction structure for at least the first wavelength and the second wavelength.

21. The spectrometry device as claimed in claim 19, wherein the at least one optical grating is configured to diffract only a partial range of visible light within a predefined wavelength range at a predetermined angle in dependence on a grating constant.

22. The spectrometry device as claimed in claim 21, wherein the measuring region and the transceiver region are one of incorporated directly into a surface structure of the carrier medium, and formed separately from the carrier medium.

23. The spectrometry device as claimed in claim 11, wherein the transceiver device further comprises a second light source to emit second light having a second wavelength onto the transceiver region of the carrier medium, wherein the predefined transceiver deflection structure of the transceiver region is configured to couple the second light emitted by the second light source into the carrier medium towards the measuring region, wherein the detection device is configured to determine a second intensity signal of the second wavelength, and wherein the evaluation unit is configured to determine a blood oxygen saturation as a medical characteristic value from the first intensity signal and the second intensity signal.

24. The spectrometry device as claimed in claim 23, wherein the second wavelength is in a range of 850 nm to 1000 nm.

25. The spectrometry device as claimed in claim 23, wherein the detection device is configured to distinguish between the first wavelength and the second wavelength.

26. The spectrometry device as claimed in claim 11, further comprising a housing configured to protect the transceiver region and the transceiver device from outside light.

27. The spectrometry device as claimed in claim 11, wherein each of the predefined transceiver deflection structure and the predefined measuring deflection structure have at least one optical grating.

28. The spectrometry device as claimed in claim 27, wherein the at least one optical grating is one of a surface holographic grating and a volume holographic grating having a multiplex diffraction structure for at least the first wavelength and the second wavelength.

29. The spectrometry device as claimed in claim 27, wherein the at least one optical grating is configured to diffract only a partial range of visible light within a predefined wavelength range at a predetermined angle in dependence on a grating constant.

30. The spectrometry device as claimed in claim 11, wherein the measuring region and the transceiver region are one of incorporated directly into a surface structure of the carrier medium, and formed separately from the carrier medium.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] These and other aspects and advantages will become more apparent and more readily appreciated from the following description of the exemplary embodiments, taken in conjunction with the accompanying drawings of which:

[0029] FIG. 1 is a schematic side view of a spectrometry device according to a first exemplary embodiment;

[0030] FIG. 2 is a schematic side view side view a spectrometry device according to a second exemplary embodiment.

DETAILED DESCRIPTION

[0031] In the exemplary embodiments explained hereinafter, the described components of the embodiments each represent individual features to be considered independently of one another, which each also refine the invention independently of one another. The disclosure is therefore also to include combinations of the features of the embodiments other than those shown. Furthermore, the described embodiments can also be supplemented by further features already described.

[0032] In the figures, identical reference signs each identify functionally identical elements.

[0033] FIG. 1 shows a schematic illustration of a spectrometry device 10 for noninvasive measurement of at least one medical characteristic value on biological tissue. The spectrometry device 10 includes a carrier medium 12, which is formed as a light guide for transmitting coupled-in light by internal reflection.

[0034] The carrier medium 12 is formed in this case using separate cuboid elements, thus plates, which are constructed in a sandwich design to form the carrier medium. The carrier medium 12 includes, for example, two plastic plates or glass plates here, which are used as the light guide and form the cover layers of the carrier medium. A core of the carrier medium can be formed, for example, by a holographic optical element, which is referred to here as the holographic element 14, and which can be formed, for example, as a transparent photopolymer film. The glass plates press directly with a respective surface on each of opposing surfaces of the holographic element. In other words, the holographic element 14 and the glass plates press flatly against one another with their respective faces enclosed by a length side and a width side. FIG. 1 shows in particular a sectional view of the spectrometry device 10, in which the spectrometry device 10 is shown with a section along a longitudinal axis.

[0035] The carrier medium 12 can include a transceiver region 16 and a measuring region 18, which are arranged offset along a longitudinal extension direction of the carrier medium. In particular, the transceiver region 16 and the measuring region 18, as shown in this embodiment, can be formed at different ends in a longitudinal direction of the carrier medium.

[0036] The holographic element 14, which is located in the transceiver region 16, can have been exposed by a holography method, whereby a predefined transceiver deflection structure 20 can form, which can be formed in particular as a volume holographic grating. This means that the transceiver deflection structure 20 has a grating structure which can diffract light having a predefined wavelength at a predetermined angle.

[0037] Similarly thereto, the holographic element 14 can have been exposed in the measuring region 18 using a holography method, whereby a measuring deflection structure 22 can form, which is also formed in this example as a volume holographic grating.

[0038] A transceiver device 24, which is arranged, for example, centrally on one of the glass plates of the carrier medium in the transceiver region, can be provided on a surface of the carrier medium in the transceiver region 16. The transceiver device 24 can include a first light source 26, which is designed to emit light having a first wavelength onto the transceiver region 16. In particular, the first light source 26 can have a light-emitting diode or a laser diode, which emits light having a first wavelength, wherein the light having the first wavelength can be in a range from 600 nm to 800 nm, in particular at 660 nm. Furthermore, a detection device 28 can be provided in the transceiver device 24, which is light-sensitive and can determine at least one first intensity signal of the first wavelength. For example, the detection device 28 can have a photodiode which can change a photocurrent upon exposure in dependence on the intensity of the incident light, whereby a first intensity signal is determinable.

[0039] A mode of operation of the spectrometry device 10 shown in FIG. 1 is to be explained on the basis of an example hereinafter. In the exemplary embodiment shown in FIG. 1, it can be provided that a pulse frequency is to be determined as a medical characteristic value. For this purpose, the first light source 26 of the transceiver device 24 can emit, for example, light having a wavelength of 660 nm into the transceiver region 16 of the carrier medium 12, which is indicated as a dashed line in the figure. The light of the first wavelength can then be diffracted at the volume holographic grating of the transceiver deflection structure 20 in such a way that the light is coupled into the carrier medium 12 in the direction of the measuring region and is transmitted by internal reflection, that is to say total reflection, to the measuring region 18 (dashed line).

[0040] In the measuring region 18, the volume holographic grating of the measuring deflection structure 22 can then diffract the light in the direction of a surface of the carrier medium, wherein a finger 30 rests on the surface of the carrier medium, for example, as biological tissue to be measured. The light emitted onto the finger, in particular the light having the wavelength of 660 nm, can enter the biological tissue and can be scattered and thus reflected, for example, at blood inside the finger 30. The reflected light, which is indicated as a dotted line, can then enter back into the measuring region 18 and can be coupled by the measuring deflection structure 22 back into the carrier medium 12, where it is then conducted back to the transceiver region 16 and can be decoupled by the transceiver deflection structure 20 onto the transceiver device 24. The detection device 28 can then record the light of the first wavelength of 660 nm reflected from the finger 30 as an intensity signal, wherein the intensity signal can change periodically in accordance with a pulse of the blood flowing through the finger 30.

[0041] An evaluation unit 32 can then determine a pulse frequency signal from the intensity signal, for example, by a Fourier analysis of the intensity signal.

[0042] A spectrometry device 10 according to a second exemplary embodiment is shown in FIG. 2. In the general structure, the second spectrometry device 10 is designed identically to the spectrometry device according to the first embodiment, i.e., having the carrier medium 12 which is formed in a sandwich construction having two glass panes as cover layers and the holographic optical element 14 in between. Furthermore, the spectrometry device 10 of the second embodiment has the transceiver device 24 and the transceiver region 16 and the measuring region 18.

[0043] In addition to the first embodiment of the spectrometry device 10, the transceiver device 24 includes, in addition to the first light source 26, a second light source 34, which can be designed as a light-emitting diode or laser diode and can emit a second wavelength in a range from 850 nm to 1000 nm, such as 940 nm.

[0044] In the second embodiment, the predefined transceiver deflection structure 20 and the predefined measuring deflection structure 22 can have a volume holographic grating, which is formed in this embodiment as a multiplex diffraction structure. The multiplex diffraction structure means that the holographic optical element 14 has been exposed during the production in the transceiver region or measuring region in such a way that two grating structures can be created interlaced with one another, so that a Bragg angle can result for the respective wavelength used, which only diffracts the wavelengths of the first and second light source 26, 34 at the predetermined angle, so that only this light can be coupled into and decoupled from the carrier medium 12. The multiplex diffraction structure can also have successive volume gratings, wherein for this purpose respective successive volume gratings are formed for a predefined wavelength. In this way, the advantage results that only light having the respective predefined wavelength is coupled into the carrier medium 12 and ambient light which does not contribute to the measurement can be filtered out, whereby signal noise at the detection device 28 can be reduced.

[0045] The detection device 28 can be designed in this embodiment to distinguish between the first wavelength and the second wavelength. This can be achieved, for example, by beam splitters or color filters in the detector. By discrimination of the wavelengths inside the detection device 28, a first intensity signal of the first wavelength and a second intensity signal of the second wavelength can then be determined, from which reflection or absorption characteristics of the biological tissue, in particular the blood, can be determined in different spectral ranges. A blood oxygen saturation can then be determined therefrom by the evaluation unit 32 by known methods as a medical characteristic value.

[0046] To protect the detection device 28 from outside light, which can interfere with the measurement, in addition a housing 36 can be provided, which is produced from a light-opaque, i.e., light-absorbing material. For example, the housing 36 can be a matte plastic housing or a housing made of metal. The housing 36 is not restricted to the second embodiment, but rather can also be provided for the first embodiment.

[0047] Using the spectrometry device 10 according to one of the two embodiments, the measuring region 18 can be arranged remotely from the transceiver region 16, whereby a flatter structure can result, which saves space and enables a better access to the measuring region.

[0048] Overall, the examples show how a pulse oximetry can be achieved via a holographic optical element.

[0049] A description has been provided with particular reference to preferred embodiments thereof and examples, but it will be understood that variations and modifications can be effected within the spirit and scope of the claims which may include the phrase “at least one of A, B and C” as an alternative expression that means one or more of A, B and C may be used, contrary to the holding in Superguide v. DIRECTV, 358 F3d 870, 69 USPQ2d 1865 (Fed. Cir. 2004).