DEVICE AND METHOD FOR IMPROVED INDUCTION OF NOISE BY MEANS OF ELECTROMAGNETIC RADIATION

Abstract

Provided herein is a device for improved induction of sound by electromagnetic radiation, comprising a carrier layer; a first substance having a reflective property with respect to electromagnetic radiation having a predetermined wavelength spectrum; and a second substance having an absorptive property with respect to electromagnetic radiation having said predetermined wavelength spectrum; wherein said first substance is disposed in a region between said carrier layer and said second substance. Furthermore, a corresponding method is provided.

Claims

1. A device, comprising: a carrier layer; a first substance having a reflective property with respect to electromagnetic radiation having a predetermined wavelength spectrum; a second substance having an absorbing property with respect to electromagnetic radiation having the predetermined wavelength spectrum; wherein the first substance is disposed in a region between the carrier layer and the second substance.

2. The device according to claim 1, wherein said carrier layer comprises two abutting layers.

3. The device according to claim 2, wherein the first layer comprises a silicone elastomer, preferably SSA MG 7-9800, and the second layer comprises a silicone elastomer, preferably Sylgard 184.

4. The device according to claim 1, wherein the first substance forms a first functional layer disposed on the carrier layer.

5. The device according to claims 2 and 4, wherein the first functional layer is arranged on the second layer of the carrier layer.

6. The device according to claim 4, wherein the second substance forms a second functional layer disposed on the first functional layer.

7. Hearing aid device, comprising: the device according to any one of claims 1 to 6; a signal generator arranged to record sound by means of at least one microphone and to emit electromagnetic radiation having the predetermined wavelength spectrum based on the recorded sound.

8. Device according to any one of claims 1 to 6 for use in a method for mechanical excitation of the eardrum by means of electromagnetic radiation.

9. Use of the device according to any one of claims 1 to 6 for mechanical excitation of the tympanic membrane, wherein the device is mounted on the tympanic membrane or another vibratable structure of the skull.

10. A method for mechanical excitation of the tympanic membrane or a further vibratable structure of the skull by means of electromagnetic radiation, comprising: attaching the device according to any one of claims 1 to 6 to the eardrum or the further vibratable structure of the skull; irradiating the device with electromagnetic radiation having the predetermined wavelength spectrum.

Description

[0025] In the following, embodiments of the invention are described with reference to the accompanying drawings.

[0026] FIG. 1 shows an example of the device according to the invention,

[0027] FIG. 2 shows a diagram illustrating a comparison between acoustic and optoacoustic stimulation of the eardrum,

[0028] FIG. 3 shows a flowchart illustrating an embodiment of the method according to the invention for mechanical stimulation of the tympanic membrane or another vibratory structure of the skull by means of electromagnetic radiation,

[0029] FIG. 4A shows an electron microscopy image of the support layer usable for the device, and

[0030] FIG. 4B shows a light microscopic image of the carrier layer usable for the device.

[0031] FIG. 1 shows an exemplary device 2 according to the invention. In the example shown, it is arranged on a tympanic membrane 1. The device 2 has a carrier layer 3. The device 2 has a first substance 4 which forms a first layer and has a reflective property with respect to electromagnetic radiation with a predetermined wavelength spectrum. Further, the device 2 comprises a second substance 5 forming a second layer having an absorbing property with respect to electromagnetic radiation having the predetermined wavelength spectrum. As shown, the first substance 4 is arranged in a region between the carrier layer 3 and the second substance 5.

[0032] An optoacoustic excitation of the tympanic membrane 1 (or, as mentioned several times, of another structure of the skull capable of vibrating) is carried out by means of electromagnetic radiation which impinges on the device 2 from the lower edge of the page. The electromagnetic radiation first impinges on the second substance 5 or the corresponding material layer, which is configured to absorb the electromagnetic radiation. That portion of the electromagnetic radiation which has not been absorbed by the first substance 5 and therefore passes through the corresponding second layer is reflected by the first substance 4 or the corresponding material layer and is prevented from penetrating the carrier layer 3 and entering the deeper tissue, e.g. middle ear. The device 2 may be attached to the eardrum 1 or to another vibratable structure of the skull by means of a glue or other adhesive.

[0033] The device 2 shown in FIG. 1 can be manufactured, for example, by first producing the carrier layer 3 from the silicone elastomers SSA MG 7-9800 and Sylgard 184. For this purpose, Sylgard 184, which has a high elastic content and exhibits relatively rigid behavior, can be applied to a carrier film and polymerized at 95° C. for 1 h. An automatic squeegee can be used to adjust the film thickness. The thickness of the polymerized film of Sylgard 184 can typically be 40 μm. MG 7-9800 can then be applied to the film of Sylgard 184 and also polymerized, and a typical film thickness can be between 40 μm and 80 μm. MG 7-9800 silicone elastomer is characterized by a high viscous component and can be used for attachment to the biological tissue, such as the tympanic membrane. Experiments have shown that multiple application and release with these layered composites is possible in mice without causing perforation of the tympanic membrane. For the formation of the device 2, the two-layer layered composite formed as described can be detached from the carrier film used for its construction. The layered composite can then be used as a carrier layer 3 and the first substance 4 and then the second substance 5 can be arranged thereon, for example in the form of corresponding layers.

[0034] By using the device according to the invention for optoacoustic excitation of a biological tissue, in particular the tympanic membrane, it is possible not only to protect it from the adverse effects of permanent irradiation with electromagnetic radiation. By using the device according to the invention, primarily in comparison with direct irradiation of the biological tissue, an increase in the amplitude of the resulting auditory activation can be achieved. This aspect is illustrated in the diagram 20 in FIG. 2, in which natural acoustic excitation has been compared with optoacoustic excitation of the tympanic membrane in an animal model (guinea pig, Charles River). On the x-axis 25 the time in milliseconds is plotted and on the y-axis 26 the measured amplitude in microvolts is plotted. A total of four graphs 21-24 are shown in the diagram. The first graph 21 represents an optoacoustic excitation of the tympanic membrane by means of an exciting optical pulse with an energy of 5 μJ when using the device according to the invention on the tympanic membrane. The second graph 22 represents a natural excitation of the eardrum with a sound pressure of 87 dB (without using the device according to the invention). The third graph 23 represents an optoacoustic excitation of the tympanic membrane by means of an excitatory optical pulse with an energy of 5 μJ without using the device according to the invention, that is, when the tympanic membrane is directly irradiated. Finally, the fourth graph 24 represents a natural excitation of the eardrum with a sound pressure of 40 dB (without using the device according to the invention).

[0035] By comparing the first graph 21 with the third graph 23, it can be seen that by using the device according to the invention, a considerable increase in the excitation amplitude in the peripheral auditory system can be achieved with a constant excitation pulse. The difference in amplitude caused by using the device according to the invention is approximately equivalent to the difference between a natural excitation of the auditory system with a sound pressure of 40 dB (fourth graph 24) and 87 dB (second graph 22). Thus, the increase in oABR (optically-evoked auditory brainstem response) amplitude achievable by using the device according to the invention is significant. In particular, the use of the device enables an optoacoustic excitation of the auditory pathway which is comparable to a natural excitation with a sound pressure level above 80 dB sound pressure.

[0036] FIG. 3 shows a flowchart 30 illustrating an embodiment of the method according to the invention for mechanical excitation of the eardrum or another vibratable structure of the skull by means of electromagnetic radiation. In a first step 31, the method comprises applying the device according to the invention to the eardrum or the further vibratable structure of the skull. In a further step 32, the method comprises irradiating the device with electromagnetic radiation having the predetermined wavelength spectrum.

[0037] FIG. 4A shows an electron microscopy image of an embodiment of the carrier layer 3, which can be used for the construction of the device according to the invention. The carrier layer 3 has a two-layer structure, with a first layer 41 comprising the silicone elastomer SSA MG 7-9800 and the second layer 42 comprising the silicone elastomer Sylgard 184. In the example shown, the first layer 41 has a thickness of 158 μm and the second layer 42 has a thickness of 42 μm. The carrier layer 3 can be produced, for example, by means of spin coating, whereby the thicknesses of the individual layers can be adjusted according to need.

[0038] FIG. 4B shows an optical microscopy image of the carrier layer 3 shown in FIG. 4A.

[0039] After completion of the carrier layer 3, the first substance can be applied to the surface of the second layer 42. For this purpose, for example, a metallic mirror layer can be vapor-deposited. Subsequently, the second substance can be applied, for example a dye/lacquer by means of a spraying process.