OPTOELECTRONIC SENSOR

Abstract

An optoelectronic sensor may include a radiation source designed to emit electromagnetic radiation, a receiver designed to receive a reflection of the radiation, an optical waveguide optically coupled to the radiation source, and/or to the receiver so that an optical coupling region is formed to couple the radiation out of the sensor and to inject the reflection into the sensor to determine properties of a sample to be determined. The sensor may be configured to rest against a sample.

Claims

1. An optoelectronic sensor comprising: a radiation source configured to emit electromagnetic radiation, a receiver configured to receive a reflection of the radiation, a light waveguide optically coupled to the radiation source and/or to the receiver so that an optical coupling region is formed in order to couple the radiation out from the optoelectronic sensor and to couple the reflection into the optoelectronic sensor in order to determine properties of a sample to be examined, wherein the optoelectronic sensor configured to bear with the coupling region on the sample to be examined.

2. The optoelectronic sensor as claimed in claim 1, comprising a further light waveguide so that the radiation source and the receiver are each optically coupled to one of the light waveguides.

3. The optoelectronic sensor as claimed in claim 1, further comprising a further radiation source optically coupled to the light waveguide.

4. The optoelectronic sensor as claimed in claim 1, wherein the light waveguide further comprises a structure in order to scatter the radiation from the light waveguide.

5. The optoelectronic sensor as claimed in claim 1, further comprising a scattering element in contact with the light waveguide at least in regions in order to scatter the radiation from the light waveguide.

6. The optoelectronic sensor as claimed in claim 1, wherein the light waveguide, the radiation source and the receiver are arranged along a plane, and the light waveguide is configured in order to guide the radiation along the plane.

7. The optoelectronic sensor as claimed in claim 6, wherein the light waveguide is configured in such a way that radiation which is oriented transversely with respect to the plane is transmitted through the light waveguide.

8. The optoelectronic sensor as claimed in claim 1, wherein the radiation source emits along a plane along which the optical coupling region extends.

9. The optoelectronic sensor as claimed in claim 1, wherein the radiation source and/or the receiver are arranged outside the optical coupling region of the sensor.

10. The optoelectronic sensor as claimed in claim 1, wherein the light waveguide extends over the radiation source and the receiver.

11. The optoelectronic sensor as claimed in claim 1, wherein the radiation source comprises a semiconductor layer sequence for the radiation generation.

12. The optoelectronic sensor as claimed in claim 1, wherein the receiver comprises a photodetector.

13. The optoelectronic sensor as claimed in claim 1, wherein the optoelectronic sensor is configured to record a vital function.

14. The optoelectronic sensor as claimed in claim 1, wherein the optoelectronic sensor is configured to record a heart rate and/or a blood oxygen level.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In the embodiments and figures, components which are the same or of the same type, or which have the same effect, are respectively provided with the same references. The elements represented and their size ratios with respect to one another are not to be regarded as to scale. Rather, individual elements, in particular layer thicknesses, may be represented exaggeratedly large for better understanding.

[0030] FIGS. 1 to 5 respectively show a schematic representation of a sensor according to a respective embodiment,

[0031] FIGS. 6 to 10 respectively show a schematic representation of a sensor with a radiation path indicated according to a respective embodiment.

DETAILED DESCRIPTION

[0032] FIG. 1 shows a schematic representation of a sensor 100 according to one embodiment. The sensor 100 is, in particular, configured to record a vital function. For example, the sensor is configured to record a heart rate. As an alternative or in addition, the sensor 100 is configured to record a blood oxygen level. According to further embodiments, as an alternative or in addition, the sensor 100 is configured to determine other properties of a sample 107 to be examined.

[0033] The sensor 100 includes a radiation source 101. The radiation source 101 is adapted to generate radiation 102 (FIGS. 6 to 10), in particular electromagnetic radiation in the infrared range to the green range. The radiation source 101 includes in particular an LED, an SLED and/or a semiconductor laser. In particular the radiation source includes a semiconductor layer sequence 113 having at least one active layer for generating the radiation 102.

[0034] The sensor 100 includes a receiver 103. The receiver 103 is configured to detect a reflection 104 (FIGS. 6 to 10) of the radiation 102 after the radiation 102 has been reflected or more in the sample 107. The receiver includes, for example, a photodetector.

[0035] The radiation source 101 and the receiver 103 are each mechanically coupled to a carrier 116. Electrical coupling is furthermore possible. The carrier 116 is, for example, a circuit board.

[0036] The sensor 100 includes a light waveguide 105. The light waveguide is, for example, made of a plastic or a glass. The light waveguide 105 is configured to guide light, i.e. electromagnetic radiation, along its main propagation direction 117. Radiation is totally internally reflected inside the light waveguide at the contact surfaces with the surroundings.

[0037] In the embodiment shown, the light waveguide 105 is optically coupled on one side to the radiation source 107. Starting from this side, the light waveguide 105 extends laterally along its main propagation direction 117. The radiation source 101 is also configured to emit radiation laterally, so that the radiation 102 is coupled out from the radiation source 101 into the light waveguide 105. Arranged between the light waveguide 105 and the sample 107 in the vertical direction 119, there is structuring 110, or a scattering element 111. The latter is used for coupling the radiation guided laterally in the light waveguide 105 out in the direction 119 of the sample 107.

[0038] Optics 118 are arranged between the receiver 103 and the sample 107. These are used, for example, to deviate the beam path in the direction of the receiver 103.

[0039] In the embodiment shown, the radiation source 101, the light waveguide 105 and the receiver 103 are arranged along a common plane 112. The plane 112 corresponds to the horizontal in FIG. 1 and is oriented transversely with respect to the direction 119 and along the direction 117. During operation, the radiation source 101 consequently emits the radiation not in the direction of the sample 107 but along a surface 120 of the sample 107. In the light waveguide 105, the radiation 102 is likewise forwarded along the plane 112 transversely with respect to the direction 119. By means of the structuring 110 and/or the scattering element 111, at least a part of the radiation 102 is deviated in the direction 119 so that the radiation 102 at least partially reaches the sample 107 from the light waveguide 105. The reflection 104 then travels from the sample 107 through the optics 118 to the receiver 103. The receiver 103 is, for example, coupled to an evaluation circuit (not represented) which determines properties of the samples 107 from the signals of the receiver 103.

[0040] The sensor 100 is, in particular, in contact with the sample 107 via the structuring 110 and/or the scattering element 111 as well as the optics 118. The sensor 100 bears on the sample 107. The regions, out from which radiation can be coupled, or into which radiation can be coupled, form an optical coupling region 106. The coupling region extends along a plane 115 which is oriented substantially parallel to the surface 120 during operation.

[0041] In particular, the optical coupling region 106 is thus defined by the structuring 110 and/or the scattering element 111 as well as the optics 118. Since the radiation 102 is not coupled directly out from the radiation source 101 into the sample 107, it is possible to arrange the radiation source 101 outside the optical coupling region 106.

[0042] The sensor 100 includes an optical barrier 121 which, in particular, transmits as little as possible radiation of the wavelength which is emitted by the radiation source 101. Crosstalk between the radiation source 101 and the receiver 103 may therefore be reduced further.

[0043] The radiation source 101 is arranged laterally beside the light waveguide 105. The receiver 103 is not optically coupled to the light waveguide 105.

[0044] FIG. 2 shows the sensor 100 according to a further embodiment. The sensor 100 of FIG. 2 corresponds substantially to the sensor 100 according to FIG. 1. In contrast to FIG. 1, according to FIG. 2 a further light waveguide 108 is provided. The light waveguide 105 is optically coupled to the radiation source 101. The further light waveguide 108 is optically coupled to the receiver 103.

[0045] During operation, the radiation 102 emitted laterally by the radiation source 101 is initially forwarded laterally by the light waveguide 105. The radiation is vertically coupled out at least partially, and is reflected at least partially by the sample 107 (not explicitly represented in FIG. 2). The reflection 104 is initially coupled into the further light waveguide 108. The further light waveguide 108 then guides the reflection 104 to the receiver 103. The receiver 103 is consequently also sensitive in a direction which is oriented transversely with respect to the surface 120 of the sample 107.

[0046] FIG. 3 shows the sensor 100 according to a further embodiment. In contrast to the embodiment of FIG. 1, the receiver 103 is not arranged in the same plane 112 as the light waveguide 105 and the radiation source 101. According to FIG. 3, the receiver 103 is arranged in a further plane 123. The plane 123 is separated from the plane 112 along the direction 119.

[0047] The light waveguide extends along the plane 112, starting from the radiation source 101, along the coupling region 106 over the receiver 103. A relatively large coupling region 106 may therefore be produced. A holding element 122 or a plurality of holding elements 122 are provided in order to fasten the light waveguide 105 and the radiation source 101 on the carrier 116.

[0048] FIG. 4 shows a further embodiment of the sensor 100. The sensor 100 is constructed in substantially the same way as the sensor 100 according to FIG. 3. In contrast to the sensor of FIG. 3, the sensor according to FIG. 4 includes a radiation source which emits out along the direction 119 transversely with respect to the plane 112. The radiation source 101 and the receiver 103 are arranged in the plane 112. The light waveguide 105 is arranged along the plane 123, which is spaced apart from the plane 112 in the direction 119.

[0049] The radiation 102 is emitted in the direction of the sample 107. It does not travel directly to the sample 107, however, but is initially coupled into the light waveguide 105. To this end, the light waveguide includes an input coupling structure 124. The latter may be a structuring of the light waveguide 105 or an extra component which improves the coupling of the radiation 102 from the radiation source 101 into the light waveguide 105.

[0050] In the light waveguide, the radiation is then forwarded transversely with respect to the emission direction along the plane 123 in the direction of the coupling region 106. The structuring 110 and/or the scattering element 111 are arranged in the coupling region 106, so that the radiation can leave the light waveguide 105. The receiver 103 is also arranged in the coupling region 106 so that the reflection 104 can travel, starting from the sample 107, through the light waveguide 105 to the receiver 103. The light waveguide 105 extends, in particular, over the radiation source 101 and the receiver 103. In particular, a uniform appearance is therefore produced on that side of the sensor 101 which faces toward the sample during operation.

[0051] FIG. 5 shows the sensor 100 according to a further embodiment. In addition to the radiation source 101, the sensor 100 according to FIG. 5 includes a further radiation source 109. In particular, the radiation source 101 and the further radiation source 109 are configured to emit radiation with different wavelengths to one another. The radiation source 101 and the further radiation source 109 are each optically coupled to the same light waveguide 105. Radiation of the radiation source 101 is coupled into the light waveguide 105. Radiation of the further radiation source 109 is likewise coupled into the same light waveguide 105. According to further embodiments, two separate light waveguides 105 and 108 are provided, each of which is coupled only to a single radiation source.

[0052] The light waveguide 105 extends along the entire optical coupling region 106 and also covers the receiver 103. The receiver is, for example, arranged between the radiation sources 101 and 109. The radiation sources 101 and 109 emit the radiation 102 primarily along the direction 119. The barrier 121 may therefore be omitted. Both the radiation of the radiation source 101 and the radiation of the further radiation source 109 are initially diverted laterally by the light waveguide 105 before they reach the sample 107.

[0053] FIG. 6 shows the sensor 100 with the radiation path of the radiation 102 and of the reflection 104 according to one embodiment.

[0054] The radiation 102 is initially emitted laterally by the radiation source 101 into the light waveguide 105. There, the radiation 102 is guided, in particular, parallel to the surface 120. In order to couple the radiation out from the light waveguide 105 in the direction of the sample 107, the scattering element 111 is provided. The scattering element 111 includes, in particular, contact regions in which there it is in contact with the light waveguide 105. Between these, the scattering element 111 includes regions in which it is arranged at a distance from the light waveguide 105. In the coupling regions, there is not a sufficiently large refractive index jump, so that the radiation 102 travels from the light waveguide 105 into the scattering element 111 and from there in the direction of the sample 107. In order to influence the beam path further, according to embodiments, the scattering element 111 includes optics 125. The optics 125 are, for example, produced with the aid of materials having different refractive indices. The reflections 104 likewise initially travel again to the scattering element 111 and are forwarded by the scattering element 111 and/or the optics 125 in the direction of the receiver 103.

[0055] FIG. 7 shows the sensor 100 according to a further embodiment. In contrast to the sensor 100 according to FIG. 6, according to FIG. 7 the separate scattering element 111 is omitted. Instead, the light waveguide 105 itself includes structurings 110. The structurings 110 are, in particular, introduced fully or in regions on that surface of the light waveguide 105 which faces toward the sample 107 during operation. The structurings 110 are used to scatter the radiation 102 transversely with respect to the main propagation direction 117 of the light waveguide 105. The structuring 110 is, for example, a roughening of the surface of the light waveguide 105. The reflection 104 may pass through the light waveguide 105 transversely with respect to its main propagation direction 117, in order to reach the receiver 103.

[0056] FIG. 8 shows a further embodiment of the sensor 100. The radiation source 101 is configured to emit the radiation 102 along the direction 119. The radiation 102 is initially coupled into the waveguide 105 and is guided by the latter along its main propagation direction 117. With the aid of the scattering element 111, the radiation 102 is subsequently directed in the direction of the sample 107 again. The reflection 104 is guided to the receiver 103 by means of the further scattering element 111. The two scattering elements 111 are in particular, arranged next to one another along the main propagation direction 117. The light waveguide 105 and the receiver 103 are arranged in a common plane 112. The radiation source 101 is arranged in the spaced-part further plane 123.

[0057] FIG. 9 shows the sensor 100 according to a further embodiment. The radiation source 101 is arranged outside the coupling region 106. The radiation source 106 is arranged in a region of the sensor 100 which, for example, is not in contact with the sample 107. By means of the light waveguide 105, the radiation 102 is guided to the coupling region 106.

[0058] FIG. 10 shows the sensor 100 according to a further embodiment. The radiation source 101, the light waveguide 105, the further light waveguide 108 and the receiver 103 are arranged in a common plane 112. The light waveguide 105 is used to guide the radiation 102 along the plane 112. The further light waveguide 108 is used to guide the reflection 104 along the plane 112 to the receiver 103. A respective scattering element 111 having optics 125 is arranged both on the light waveguide 105 and on the further light waveguide 108.

[0059] The sensor 100 with the light waveguide 105 allows compact construction with a good signal-to-noise ratio and an improved esthetic appearance. According to one embodiment, the radiation source 101 is optically coupled to the light waveguide 105. According to one embodiment, the light waveguide 105 is arranged on the receiver 103 or next to the receiver 103. According to embodiments, the radiation 102 is coupled out from the light waveguide 105 in the direction of the sample 107 by means of the structuring 110. The structuring 110 includes, in particular, a microstructured profile. The radiation 102 is scattered and reflected in the sample 107, and subsequently collected and guided to the receiver 103. According to embodiments, to this end the light waveguide 105 is either used, i.e. the same optical system. According to further embodiments, the further light waveguide 108 and/or further optics such as the scattering element 111 and the optics 125 are used.

[0060] The radiation source 101 may be arranged above the light waveguide 105 (FIGS. 4, 5, 8, 9). According to further embodiments, the radiation source 101 is arranged next to the light waveguide 105 (FIGS. 1, 2, 3, 6, 7, 10). According to embodiments, the input coupling structure 124 is used when the radiation source 101 is arranged above the light waveguide 105, in order to couple the radiation 102 from the light source 101 into the light waveguide 105. The input coupling structure 125 may be configured either to refract light or diffract light.

[0061] According to embodiments, a plurality of radiation sources 101, 109 are coupled to the same light waveguide 105. In particular, the radiation sources 101, 109 have different wavelengths to one another of the emitted radiation 102. This is advantageous in particular when measuring the oxygen level of blood. Furthermore, a signal improvement may be achieved.

[0062] According to embodiments, the structuring 110 is integrated directly on the light waveguide 105 (FIG. 7). According to further embodiments, as an alternative or in addition, the separate scattering element 111 is provided. According to embodiments, a plurality of optical surfaces are provided on the side facing toward the sample, in order to further improve the signal-to-noise ratio by a predetermined distribution of the radiation intensity and collection of the reflection 104. This is achieved, for example, by a predetermined arrangement of the regions in which the scattering element 111 is in direct contact with the light waveguide 105, and of the regions in which the scattering element 111 is at a distance from the light waveguide 105.

[0063] The scattering element 111 and/or the input coupling structure 124 may refract light and/or diffract light.

[0064] According to at least one embodiment, the light waveguide 105 includes an antireflection coating or a correspondingly treated surface. This reduces the radiation 102 travelling directly to the receiver 103 instead of into the waveguide 105, for example by Fresnel reflection.

[0065] In particular when the sensor 100 is used as a sensor for determining a vital function, when the sensor 100 is in contact with the skin of a human during operation, the contact region of the sensor 100 is configured as flatly as possible without the structuring 110 directly in the light waveguide 105. The functionality of the structure 110 could be impaired by dust and/or grease. The use of the separate scattering element 111 may therefore be advantageous.

[0066] The radiation 102 which has been coupled into the light waveguide 105 can no longer travel directly to the receiver 103. Even with a short distance between the receiver 103 and the radiation source 101, crosstalk of the radiation 102 directly to the receiver 103 is therefore sufficiently small. The size of the sensor 101 may therefore be reduced. Furthermore, the light waveguide 105, the scattering element 111 and/or the further optical elements serve as protection for the radiation source 101 and/or the receiver 103. Conventionally additionally provided protective layers may therefore be omitted.

[0067] The receiver 103 and/or the radiation source 101, and optionally further components of the sensor 100, are covered in one direction by the light waveguide 105, or the scattering element 111. They are therefore no longer visible, or less visible. The esthetic appearance of the sensor 100 is therefore enhanced. By means of the lightguide structure with the light waveguide 105 and/or the light waveguide 108 and/or the scattering element 111, and optionally further optical layers, it is possible to distribute the distribution of the radiation 102 along the optical coupling region 106 in a predetermined way. Furthermore, recording of the reflections 104 at a fixed angle is possible. An improvement in the signal-to-noise ratio is therefore made possible, and inaccuracies during the measurement are therefore reduced.

[0068] The invention is not restricted by the description with the aid of the embodiments to the latter. Rather, the invention covers any new feature and any combination of features, which includes in particular any combination of features in the patent claims, even if this feature or this combination is not explicitly indicated per se in the patent claims or embodiments. In particular, any combination of individual features of the various configurations of the sensor 100 in FIGS. 1 to 10 is possible. The different arrangement and configuration of the radiation source 101, of the receiver 103, of the light waveguides 105 and 108 and of the further radiation source 109 and of the other elements may respectively be combined individually with the configurations of other figures. The various configurations of the elements of the sensor 100 of the various embodiments may be combined with one another in different combinations.

LIST OF REFERENCES

[0069] 100 sensor [0070] 101 radiation source [0071] 102 electromagnetic radiation [0072] 103 receiver [0073] 104 reflection [0074] 105 light waveguide [0075] 106 optical coupling region [0076] 107 sample [0077] 108 further light waveguide [0078] 109 further radiation source [0079] 110 structuring [0080] 111 scattering element [0081] 112 plane [0082] 113 semiconductor layer sequence [0083] 114 photodetector [0084] 115 plane of the coupling region [0085] 116 carrier [0086] 117 main propagation direction [0087] 118 optics [0088] 119 direction [0089] 120 surface [0090] 121 barrier [0091] 122 holding element [0092] 123 plane [0093] 124 input coupling structure [0094] 125 optics