METHOD FOR CHECKING A PPG SENSOR OF A HEARING APPARATUS, AND HEARING APPARATUS SYSTEM

Abstract

A method for checking a PPG sensor of a hearing apparatus that has a rechargeable battery. A charger has a receiving space for the hearing apparatus and a testing environment for testing the functionality of the PPG sensor. The hearing apparatus is placed in the receiving space and the test environment is used to perform a function test on the PPG sensor.

Claims

1. A method of checking a photoplethysmography (PPG) sensor of a hearing apparatus that has a rechargeable battery, the method which comprises: providing a charger with a receiving space for the hearing apparatus, the charger having a test environment for the PPG sensor; positioning the hearing apparatus in the receiving space; and using the test environment to perform a function test on the PPG sensor.

2. The method according to claim 1, which further comprises outputting a report concerning a functionality of the PPG sensor to a user of the hearing apparatus when a result of the function test falls short of a predefined limit value.

3. The method according to claim 1, wherein the function test comprises using a wall of the receiving space as a reflection surface for the PPG sensor.

4. The method according to claim 1, wherein the test environment for the PPG sensor includes a test light source and the function test comprises illuminating the PPG sensor by the test light source, receiving a measure output by the PPG sensor for a detected amount of light, and comparing the measure output by the PPG sensor with a corresponding measure of an amount of light emitted by the test light source.

5. The method according to claim 4, wherein the test light source is of a same type light source as a light source of the PPG sensor.

6. The method according to claim 4, which comprises actuating the test light source using a predefined value of an electrical control variable to illuminate the PPG sensor, and using the control variable as a measure of an emitted amount of light.

7. The method according to claim 6, wherein the electrical control variable is an electric current.

8. The method according to claim 1, wherein the test environment for the PPG sensor includes a test photodetector and the function test comprises illuminating the test photodetector by the PPG sensor and comparing a measure output by the test photodetector for a detected amount of light with a corresponding measure of an amount of light emitted by the PPG sensor.

9. The method according to claim 8, wherein the test photodetector is of a same type as a photodetector of the PPG sensor.

10. The method according to claim 8, which comprises actuating the PPG sensor using a predefined value of an electrical control variable to illuminate the test photodetector and using the control variable as a measure of the emitted amount of light.

11. The method according to claim 10, wherein the step of actuating the PPG sensor comprises actuating a light source of the PPG sensor.

12. The method according to claim 1, wherein: the test environment for the PPG sensor includes a test light source and the function test comprises illuminating the PPG sensor by the test light source, receiving a measure output by the PPG sensor for a detected amount of light, and comparing the measure output by the PPG sensor with a corresponding measure of an amount of light emitted by the test light source; and the test environment for the PPG sensor includes a test photo-detector and the function test comprises illuminating the test photodetector by the PPG sensor and comparing a measure output by the test photodetector for a detected amount of light with a corresponding measure of an amount of light emitted by the PPG sensor.

13. The method according to claim 12, which comprises performing a preliminary test for the function test by using the PPG sensor and/or the test photodetector to ascertain a brightness measured variable as a measure of a distance between the PPG sensor and the test photodetector and/or the test light source.

14. The method according to claim 13, which comprises performing the function test only when the brightness measured variable satisfies a predefined criterion.

15. The method according to claim 13, which comprises transferring the measure of the detected amount of light, the measure of the emitted amount of light, and/or the brightness measured variable from the hearing apparatus to the charger for comparison with a particular corresponding measure or with a predefined criterion and comparing with a particular corresponding measure or criterion by the charger by way of a controller configured for that purpose.

16. The method according to claim 4, which comprises performing a preliminary test for the function test by using the PPG sensor to ascertain a brightness measured variable as a measure of a distance between the PPG sensor and the test light source.

17. The method according to claim 16, which comprises transferring the measure of the detected amount of light, the measure of the emitted amount of light, and/or the brightness measured variable from the hearing apparatus to the charger for comparison with a particular corresponding measure or with a predefined criterion and comparing with a particular corresponding measure or criterion by the charger by way of a controller configured for that purpose.

18. The method according to claim 8, which comprises performing a preliminary test for the function test by using the test photodetector to ascertain a brightness measured variable as a measure of a distance between the PPG sensor and the test photodetector.

19. The method according to claim 18, which comprises transferring the measure of the detected amount of light, the measure of the emitted amount of light, and/or the brightness measured variable from the hearing apparatus to the charger for comparison with a particular corresponding measure or with a predefined criterion and compared with a particular corresponding measure or criterion by the charger by way of a controller configured for that purpose.

20. A hearing apparatus system, comprising: a hearing apparatus with a photoplethysmography (PPG) sensor and a rechargeable battery; and a charger formed with a receiving space for said hearing apparatus and a test environment for testing said PPG sensor; and at least one controller configured to perform the method according to claim 1.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0047] FIG. 1 shows a schematic side view of a hearing apparatus;

[0048] FIG. 2 shows a schematic side view of a hearing apparatus system that includes the hearing apparatus shown in FIG. 1 and a charger; and

[0049] FIGS. 3-5 each shows a view similar to FIG. 2 for a further exemplary embodiment of the hearing apparatus system.

[0050] Mutually corresponding parts and variables are provided with identical reference signs throughout the figures.

DETAILED DESCRIPTION OF THE INVENTION

[0051] Referring now to the figures of the drawing in detail and first, in particular, to FIG. 1 thereof, there is shown a hearing apparatus in the form of a hearing aid, specifically a hearing aid to be worn behind the ear of a user (also referred to as a hearing device, here as “BTE 1”, for short). The BTE 1 includes a housing 2 in which electronic components of the BTE 1 are arranged. These electronic components are for example two microphones 4, a signal processor 6 and a battery module 8, which in turn includes a rechargeable battery. When the BTE 1 is operating as intended, the microphones 4 are used to receive ambient sound and to convert said sound into electrical input signals (also: “microphone signals”), which are processed (in particular filtered, amplified on a frequency-dependent basis and/or attenuated, etc.) by the signal processor 6 (also referred to as “controller”). The processed input signals are subsequently output as output signals to a loudspeaker, not shown, and are converted into sound signals by the latter and forwarded to the ear of the user.

[0052] The BTE 1 additionally comprises a photoplethysmography sensor, “PPG sensor 12” for short, which is likewise inserted in the housing 2 in the present exemplary embodiment. The PPG sensor 12 is used for example to ascertain the pulse, optionally also the oxygen saturation, of the user of the BTE 1. To this end, the PPG sensor 12 includes a light source, in the present case an LED unit 16, which is configured to output light in multiple frequency bands, but usually at least light in the near infrared range. Additionally, the PPG sensor 12 comprises a light sensor 18 (“photodetector”) by means of which radiated light is detected. When operating as intended, the light sensor 18 detects radiation that is output by the LED unit 16 and reflected by body tissue, for example a vascular wall of a blood vessel of the user. The intensity profile detected in the process can then be used to determine the pulse of the user, for example.

[0053] FIG. 2 shows a hearing apparatus system 20 in more detail. Said system includes the BTE 1 described above and a charger 22. The latter is used to recharge the rechargeable battery of the BTE 1. To this end, the charger 22 comprises a receiving space 26 in which the BTE 1 is positioned in the intended charging state (see FIG. 2). The charger 22 provides a test environment for the BTE 1, specifically for the PPG sensor 12 thereof. Additionally, the charger 22 has a lid 28 by means of which the receiving space 26 is sealable.

[0054] An example of a method for checking the function of the PPG sensor 12 is described in more detail below with reference to FIG. 2. In this scenario, the BTE 1, specifically using the signal processor 6 thereof, performs a self-test on the PPG sensor 12. In the example shown in FIG. 2, the test environment is used to provide preferably repeatable and stable conditions for the self-test on the PPG sensor 12. To this end, a wall of the receiving space 26 is equipped with a reflective surface 30 of predefined “quality” when the BTE 1 is in the intended state of insertion in the receiving space 26. By way of example, this surface 30 is white, but not shiny, in order to allow light to be scattered in preferably all directions (“diffuse scatter/reflection”). During the self-test, the signal processor 6 actuates the PPG sensor 12 in order to use the LED unit 16 to output a light signal (“test signal”) L.sub.S having a predefined amount of light (or: radiation intensity). The light sensor 18 is used to detect at least a portion of the light signal L.sub.S that is reflected from the surface 30. The measure used for the detected amount of light is a photocurrent S.sub.P that is then output by the light sensor 18. The value of said photocurrent is compared with a measure of the emitted amount of light, here specifically a control variable, in particular a control current S.sub.C, by means of which the LED unit 15 is actuated. If the value of the photocurrent S.sub.P exceeds a limit value G.sub.S, which is predefined on the basis of the nature of the surface 30, it may be assumed that the PPG sensor 12 is functional. If this limit value G.sub.S is fallen short of, or undershot, the signal processor 6 outputs a report to the user of the BTE 1. In this report, the signal processor 6 indicates to the user that the PPG sensor 12 is not functioning as intended. For example, it may be soiled.

[0055] Optionally, the comparison with the limit value G.sub.S takes place in a controller 32 of the charger 22. In this case, the signal processor transmits the value of the control current S.sub.C and of the photocurrent S.sub.P to the controller 32 of the charger 22 by means of a transmitter 34.

[0056] FIG. 3 describes an alternative exemplary embodiment of the hearing apparatus system 20 and of the method for checking the function of the PPG sensor 12 that is performed by means of said system. Besides the surface 30 described above, the charger 22 also has a test light source 36. This is of the same type, specifically the same design, as the LED unit 16 of the PPG sensor 12 and is thus able to emit light of the same wavelength(s). Additionally, the test light source 36 is positioned in the receiving space 26 in such a way that it is arranged in juxtaposition with the PPG sensor 12 when the BTE 1 is positioned as intended.

[0057] In addition or as an alternative to the approach described above, this test light source 36 is optionally used to test the light sensor 18 separately during the function check. To this end, the charger 22 uses the test light source 36 to emit a test light signal L.sub.T in the direction of the PPG sensor 12. If said signal is detected by means of the light sensor 18, the BTE 1 sends the ascertained photocurrent S.sub.P to the controller 32 of the charger 22. Said controller compares the photocurrent S.sub.P (the value thereof) with its own control current S.sub.CL (specifically the value thereof) output to the test light source 36. If the values of the two variables are sufficiently similar, the controller 32 infers that the light sensor 18 is functional. Otherwise, the controller 32 outputs a warning. If the self-test described above is subsequently performed when the light sensor 18 is functional, and the limit value G.sub.S is fallen short of in the process, this indicates a malfunction in the LED unit 16. An appropriate warning is then output.

[0058] FIG. 4 describes an alternative exemplary embodiment of the hearing apparatus system 20 and of the method for checking the function of the PPG sensor 12 that is performed by means of said system. Besides the test light source 36 described above for FIG. 3, the charger 22 also comprises a test photodetector (referred to as “test light sensor 38” here). This is of the same type, specifically the same design, as the light sensor 18 of the PPG sensor 12 and thus has the same detection characteristic. The test light sensor 38 is also positioned in the receiving space 26 in such a way that it is arranged in juxtaposition with the PPG sensor 12 when the BTE 1 is positioned as intended.

[0059] In addition to the approach described with reference to FIG. 3, the function check involves the light signal L.sub.S being transmitted by the LED unit 16 and at least portions of said light signal being received by means of the test light sensor 38. A corresponding test photocurrent S.sub.PT is compared by the controller 32 with the control current S.sub.C for the LED unit 16, which current was transmitted to the controller 32 by the BTE 1. That is to say that it is thus possible to check the function of the LED unit 16 and of the light sensor 18 independently of one another.

[0060] In an optional variant, the controller 32 is configured to perform a self-test for the test light source 36 and the test light sensor 38 by operating them similarly to the PPG sensor, for example when the BTE 1 is not inserted. In this case, the procedure is similar to that for the self-test described with reference to FIG. 2.

[0061] Optionally, multiple test light sources 36 are arranged in the receiving space 26. In order to ascertain which test light source 36 the PPG sensor 12 is arranged opposite “best”, i.e. specifically closest, the individual test light sources 36 are actuated in succession and the particular detected intensity is detected. The test light source 36 that brings about the “strongest” reaction is assumed to be the closest.

[0062] FIG. 5 shows a further exemplary embodiment of the hearing apparatus system 20. The BTE 1 in this case comprises a temperature sensor 50 that is in the form of a resistive temperature sensor. Said sensor is used to ascertain the body temperature of the user of the BTE 1 in the intended worn state. The charger 22 comprises an infrared temperature sensor, IR sensor for short, 52. As described above for the test light source 36, said sensor is likewise arranged in juxtaposition with the temperature sensor 50. After the BTE 1 has been inserted into the charger 22, specifically into the receiving space 26, the IR sensor 52 is used to record the temperature at the location of the temperature sensor 50. After an adjustment time, the end of which is identified from the fact that the measured temperature values do not change again, the temperature values measured by means of the temperature sensor 50 and the IR sensor 52 are compared with one another. If they differ from one another, the temperature sensor 50 is set to the value of the IR sensor 52, and therefore is “calibrated” to said value.

[0063] The subject matter of the invention is not restricted to the exemplary embodiments described above. Rather, further embodiments of the invention may be derived from the above description by a person skilled in the art. In particular, the individual features of the invention, and the configuration variants thereof, as described with reference to the various exemplary embodiments, may also be combined with one another in some other way.

[0064] The following is a summary list of reference numerals and the corresponding structure used in the above description of the invention:

1 BTE

[0065] 2 housing
4 microphone
6 signal processor
8 battery module
12 PPG sensor (photoplethysmography sensor)
16 LED unit
18 light sensor
20 hearing apparatus system
22 charger
26 receiving space
28 lid
30 surface
32 controller
34 transmitter
36 test light source
38 test light sensor
50 temperature sensor
52 IR sensor
L.sub.S light signal
L.sub.T test light signal
S.sub.C control current
S.sub.P photocurrent
G.sub.S limit value
S.sub.CL control current
S.sub.PT test photocurrent