KR100853857B1 - Optical microphone and its manufacturing method - Google Patents

Abstract

The present invention relates to an optical microphone and a method of manufacturing the same, and more particularly to a light emitting and receiving optical fiber, which is one component of an optical microphone, for the purpose of reducing the area of the head portion of a conventional optical microphone and providing ease of manufacturing processing. The present invention relates to an optical microphone and a method for manufacturing the same, which are capable of diffracting light toward a diaphragm by cutting an end surface thereof diagonally in a state of bonding to a fixing jig.

To this end, the present invention is an optical microphone including a light emitting unit (LED) and a light emitting optical fiber, a light receiving optical fiber and a light receiving unit (PHOTODETECTOR), and a diaphragm for reflecting the light emitted from the light emitting optical fiber to the light receiving optical fiber, the light emitting optical fiber And cutting the upper ends of the light emitting optical fiber and the light receiving optical fiber inclined upwardly from the outside to the inward direction while bonding the light receiving optical fiber to the fixing jig, and having a diaphragm disposed immediately above the upper ends of the light emitting optical fiber and the light receiving optical fiber. Provided are an optical microphone and a manufacturing method thereof.

Optical microphone, light emitting fiber, light receiving fiber, diaphragm, cutting, optimum cross-section processing

Description

Photonic microphone and method for fabricating the same

1 is an exemplary view illustrating a conventional optical microphone,

2 and 3 are graphs showing the amount of light generated by moving the diaphragm forward according to the voice signal and the amount of light shown by moving the diaphragm backward according to the voice signal;

4 is an exemplary diagram illustrating another conventional optical microphone;

5 is an exemplary view for explaining a method of manufacturing another conventional optical microphone;

6 is an exemplary view illustrating an optical microphone according to the present invention.

<Explanation of symbols for the main parts of the drawings>

10: light emitting unit

12: light emitting optical fiber

14: light receiving optical fiber

16: light receiver

18: diaphragm

20 lens

22: fixing jig

The present invention relates to an optical microphone and a method of manufacturing the same, and more particularly to a light emitting and receiving optical fiber, which is one component of an optical microphone, for the purpose of reducing the area of the head portion of a conventional optical microphone and providing ease of manufacturing processing. The present invention relates to an optical microphone and a method for manufacturing the same, which are capable of diffracting light toward a diaphragm by cutting an end surface thereof diagonally in a state of bonding to a fixing jig.

The optical microphone is based on the optical conversion technology that converts the dynamic sound signal into an optical signal. It does not generate any interference from surrounding electromagnetic fields or radiation, and has excellent sensitivity to sound pressure and excellent response characteristics in a wide frequency band. It is recognized as the next generation technology that can replace the existing condenser microphone.

In addition, since the optical microphone can detect and transmit a long distance signal using an optical transmission method using an optical fiber, the optical microphone can be efficiently distributed for continuous sound signal detection by distributing it in a large area where humans cannot easily access it at any time.

Since the optical microphone does not use an electrode and a metal, it is not only light and durable, but also has a simple structure due to its simple structure and high economic potential.

As is well known, the optical microphone detects the amount of light due to the positional change of the diaphragm and converts the acoustic signal into an optical signal. As an example of a conventional optical microphone, the configuration thereof is basically as illustrated in FIG. A light emitting unit 10 (LED) and a light emitting optical fiber 12, a light receiving optical fiber 14 and a light receiving unit 16 (PHOTODETECTOR), and a diaphragm for reflecting light emitted from the light emitting optical fiber 12 to the light receiving optical fiber 14 ( 18).

Looking at the operating principle of the optical microphone having the above configuration, the light emitted from the light emitting unit 10 (LED) is incident obliquely into the diaphragm 18 through the bundle-shaped light emitting optical fiber 12 and at the same time reflected by the diaphragm 18 After the light is incident on the light receiving optical fiber 14, the light transmitted through the light receiving optical fiber 14 is converted into an optical signal by the light receiving unit 16.

At this time, when the sound wave generated by the voice signal is incident from the rear of the diaphragm, the diaphragm moves back and forth according to the traveling direction of the sound wave, and at this time, the optical coupling efficiency changes due to the axial shift between the light emitting optical fiber and the light receiving optical fiber. Since the amount of light incident on the optical fiber changes, the output of the optical microphone changes according to the intensity of the voice signal.

2 is a diagram showing the amount of light generated by moving the diaphragm forward according to the voice signal, and FIG. 3 shows the amount of light generated by moving the diaphragm backward according to the voice signal. Can be converted into an optical signal form.

In other words, when the sound pressure increases, the displacement of the diaphragm increases, and the modulation amplitude of the optical signal increases, so that the operation of the optical microphone converts and transmits the voice signal into the optical signal form.

However, the conventional optical microphone shown in FIG. 1 has the following disadvantages.

The light emitting optical fiber 12 and the light receiving optical fiber 14 face each other inwardly in order to obliquely enter the light emitted from the light emitting unit 10 (LED) in order to detect the amount of light due to the positional change of the diaphragm 18 according to the voice signal. It has a structure that is arranged obliquely facing, this has the disadvantage that the area of the head portion of the optical microphone is widened.

That is, there is a disadvantage in that the width of the light head and the light receiving optical fiber is widened to increase the optical head portion.

In view of this point, another structure of the optical microphone has been manufactured. As shown in FIG. 4, the light emitting optical fiber 12 and the light receiving optical fiber 14 are arranged in 11 characters, and the lens 20 is disposed thereon. The optical microphone of the structure which arrange | positioned was produced.

Therefore, light from the light emitting optical fiber 12 is diffracted through the lens 20 and reflected at the diaphragm 18, and then diffracted through the lens 20 to be incident on the light receiving optical fiber 14, in this case an optical microphone. Although the area of the head portion of the can be reduced, it has a disadvantage that the manufacturing cost increases because it must configure an additional device such as a lens.

In addition, another optical microphone has been conventionally proposed as shown in FIG. 5.

That is, an optical microphone having a structure that can reduce the area of the optical head portion by cutting the upper ends of the light-emitting and light-receiving Guam fibers 12 and 14 by changing the diagonals of the light can be changed.

However, when attaching the optical fiber cut in the end section in advance to the fixing jig, there is a difficulty in aligning and bonding the end section of the cut optical fiber, there are many disadvantages in actual production.

The present invention has been made in view of the above, and in order to reduce the area of the head portion of a conventional optical microphone and to provide ease of fabrication, the jig for fixing light-emitting and light-receiving optical fibers, which is one component of the optical microphone, is provided. It is possible to diffract the light toward the diaphragm by cutting the end face diagonally in the state of bonding to the diaphragm, greatly reducing the head area of the optical microphone and providing ease of manufacture, and also providing a dynamic sound signal. Is transformed into an optical signal and does not generate any interference by electromagnetic fields or radiation, has excellent sensitivity to sound pressure, excellent response characteristics in a wide frequency band, and is light and durable because it does not use electrodes and metals. Micro-fiber that can be used to reduce the size and integration And there is provided a manufacturing method thereof.

In addition, another object of the present invention is to use a multimode-multimode optical fiber in the light emitting optical fiber and the light receiving optical fiber, it is possible to improve the sensitivity of the optical microphone by using optical fibers having a diameter of different cores.

One embodiment of the present invention for achieving the above object includes: a light emitting unit (LED) and a light emitting optical fiber, a light receiving optical fiber and a light receiving unit (PHOTODETECTOR), and a diaphragm for reflecting light from the light emitting optical fiber incident to the light receiving optical fiber In the optical microphone, the upper ends of the light emitting optical fiber and the light receiving optical fiber are inclined upwardly from the outside toward the inside in the state in which the light emitting optical fiber and the light receiving optical fiber are bonded to the fixing jig, respectively, the upper end of the light emitting optical fiber and the light receiving optical fiber An optical microphone is provided which has a structure in which a diaphragm is disposed just above an end.

In a preferred embodiment, the light emitting optical fiber and the light receiving optical fiber is applied to a multimode light emitting optical fiber and a multimode light receiving optical fiber, the multimode light emitting optical fiber uses a core fiber smaller than the multimode light receiving optical fiber, and the multimode light receiving optical fiber An optical fiber having a larger diameter of the core than the core of the multi-mode light emitting optical fiber is disposed.

Another embodiment of the present invention for achieving the above object includes: a light emitting unit (LED) and a light emitting optical fiber, a light receiving optical fiber and a light receiving unit (PHOTODETECTOR), and a diaphragm for reflecting the light from the light emitting optical fiber incident to the light receiving optical fiber In the method of manufacturing an optical microphone, the multi-mode light emitting optical fiber uses a core optical fiber of a core smaller than the multi-mode light receiving optical fiber in order to apply the light emitting optical fiber and the light receiving optical fiber as a multi-mode light receiving optical fiber and a multimode light receiving optical fiber, The mode light-receiving optical fiber comprises the steps of selecting the optical fiber having a larger diameter of the core than the core of the multi-mode light emitting optical fiber; Bonding the selected multimode light emitting optical fiber and the multimode light receiving optical fiber to a fixing jig, the upper end of which protrudes out of the upper line of the fixing jig; It provides a manufacturing method of an optical microphone comprising the step of cutting the upper end of the protruding multi-mode light emitting optical fiber and the multi-mode light receiving optical fiber along the upper line of the fixing jig.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The application field of the optical microphone according to the present invention is efficient for continuous sound signal monitoring by distributing it in a large area that is not easily accessible at any time because it is possible to detect and transmit a long distance signal by using an optical transmission method using a multimode optical fiber. In addition, it can be applied to smooth communication between patients and doctors without affecting the operation of equipment in medical equipment systems such as MRI and CT, and remotely monitoring traffic or environment in noisy places such as airports. It can be effectively used for, and in particular, it can be easily used for sensors such as accelerometer.

6 is an exemplary view illustrating an optical microphone and a method of manufacturing the same according to the present invention.

As shown in FIG. 6, the optical microphone includes a light emitting unit 10 for generating light, a light emitting and receiving multimode optical fiber 12 and 14 for transmitting light, a light receiving unit 16 for detecting light, and an acoustic And a diaphragm 18 (reflective plate) whose position is changed by a signal.

Accordingly, the optical microphone transmits light generated from the light emitting unit 10 to the diaphragm 18 through the light emitting optical fiber 12, and at the same time, the light reflected by the diaphragm 18 is transmitted through the light receiving optical fiber 14. The light is transmitted to the light receiving unit 16.

As described above, the conventional optical microphone has a disadvantage in that the volume of the head is large, and thus the size and size of the head are reversed. The present invention for solving the above-mentioned disadvantages is to maintain the volume of the head while maintaining the function of the optical microphone. The main focus is on the fact that the installation area can be greatly reduced, and that no additional means are required to reduce the manufacturing cost, and in particular, the ease of manufacturing and processing can be provided.

To this end, as shown in Fig. 6, the light emitting optical fiber 12 and the light receiving optical fiber 14 are arranged in a state of being bonded to the fixing jig 22 in the head portion of the optical microphone, and then the light emitting optical fiber 12 ) And the upper end of the light receiving optical fiber 14 are cut inclined upwardly from the outside toward the inside.

That is, as shown in FIG. 6, the uncut light emitting and receiving optical fibers 12 and 14 are aligned with the fixing jig 22 and bonded, and the light emitting and receiving optical fibers 12 and 14 bonded on the fixing jig are ground. The optical head portion is processed by cutting in the furnace.

In more detail, the light emitting optical fiber 12 and the light receiving optical fiber 14 are bonded to the fixing jig 22, the upper end of which is bonded to protrude out of the upper line of the fixing jig 22, and then the projecting light emitting optical fiber By cutting the upper end of the light receiving optical fiber 14 and the light receiving optical fiber 14 along the upper line of the fixing jig 22, an optimum cross-section of the upper end of the light emitting optical fiber 12 and the light receiving optical fiber 14 is possible, and the cutting process This can be done easily.

That is, the upper end of the bundle of light emitting optical fibers 12, that is, the end surface for irradiating light to the diaphragm 18, and the upper end of the bundle of light receiving optical fibers 14, that is reflected from the vibration plate 18 End surfaces for receiving light are each formed to be inclined upwardly from the outside to the inward direction.

In addition, the diaphragm 18 is disposed directly on the upper end of the light emitting optical fiber 12 and the light receiving optical fiber 14, that is, directly above the end surface which is inclined upwardly.

In this case, in order to apply the light emitting optical fiber and the light receiving optical fiber to the multimode light emitting fiber and the multimode light receiving fiber, the multimode light emitting fiber uses a fiber of a core smaller than the multimode light receiving fiber, and the multimode light receiving fiber is a multimode light emitting fiber. Use a fiber with a larger diameter than the core of the fiber.

Meanwhile, the fixing jig 22 may be a glass plate or a plastic plate, and may be manufactured using various kinds of materials, and when the optical fiber is bonded to the fixing jig 22, the light receiving optical fiber 14 and the light emitting optical fiber ( The optical coupling efficiency varies depending on the angle of 12). At this time, the optimum path is found and bonded.

Herein, the operation of the optical fiber microphone having the optimal cross-section processed so that the upper end of the light emitting and receiving optical fiber is inclined upwardly from the outside to the inside is as follows.

The light generated by the light emitting unit 10 is transmitted obliquely to the diaphragm 18 through the light emitting multimode optical fiber, that is, the optimal cross-sectional processing, that is, the light emitting optical fiber 12, and the light is refracted when irradiated with water. In the same manner, the light is diffracted at the end surface (surface inclined upward from the outside to the inside) of the light emitting optical fiber 12 and is incident on the diaphragm 18.

Subsequently, the light irradiated to the diaphragm 18 where the positional change is caused by the acoustic signal is reflected, and is transmitted to the optimal cross-sectional light receiving multimode optical fiber, that is, the light receiving optical fiber 14, and the light reflected from the diaphragm 18 is Similarly, light is incident at an angle to the light-receiving optical fiber 14 as a phenomenon in which light is refracted when irradiated with water.

At the same time, the light transmitted to the light receiving optical fiber 14 is received by the photo detector 16, which detects the amount of light due to the positional change of the diaphragm 18 and converts the acoustic signal into an optical signal. Will be converted.

In this way, while applying the light-emitting and light-receiving optical fiber, which is one component of the optical microphone, in multimode-multimode, the end surface is cut diagonally to improve the structure of the optimal cross-section to diffract light toward the diaphragm, It is possible to greatly reduce the head area of the optical microphone and at the same time reduce the manufacturing cost and provide ease of manufacturing processing.

On the other hand, the optical microphone has different optical coupling efficiencies for monomode-monomode optical coupling, monomode-multimode optical coupling, and multimode-multimode optical coupling. It is known to be the best for optical coupling efficiency.

That is, the optical coupling efficiency is known to be good when the size of the core of the light emitting optical fiber is smaller than that of the core of the light receiving optical fiber.

This is because the light from the optical fiber has a spread angle at a certain angle. If the same core size is used, that is, if the size of the core of the light emitting fiber is the same as that of the light receiving fiber, the light transmitted from the light emitting fiber is The spread angle prevents all light from entering the optical fiber.

Therefore, if the size of the light receiving optical fiber core is larger than the size of the light emitting optical fiber core, even if the light transmitted from the light emitting optical fiber is spread by the spread angle, since the size of the core of the light receiving optical fiber is large, the light can be received. And the light receiving optical fibers 12 and 14 may use a multimode-multimode optical fiber but may use optical fibers having diameters of different cores to improve the sensitivity of the optical microphone.

As described above, according to the optical microphone according to the present invention, in the state in which the light-emitting and light-receiving optical fiber, which is one component of the optical microphone, is bonded to the fixing jig, the end surface is cut diagonally to diffract light toward the diaphragm. By making it possible, the area of the head portion of the optical microphone can be greatly reduced, and the manufacturing cost can be reduced, and in particular, the ease of fabrication can be provided.

In addition, by converting a mechanical sound signal into an optical signal, there is no interference caused by electromagnetic fields or radiation at all, it has an excellent sensitivity to sound pressure and its response characteristic is excellent in a wide frequency band.

In addition, since the electrode and the metal are not used, not only is it light and durable, but also the structure is simple, and the effect of miniaturization and integration can be obtained.

Claims (3)

delete An optical microphone comprising a light emitting portion (LED) and a light emitting optical fiber, a light receiving optical fiber and a light emitting portion (PHOTODETECTOR), and a diaphragm for reflecting light emitted from the light emitting optical fiber into the light receiving optical fiber, In the state in which the light emitting optical fiber and the light receiving optical fiber are bonded to the fixing jig, the upper ends of the light emitting optical fiber and the light receiving optical fiber are respectively inclined upwardly from the outside toward the inward direction, and a diaphragm is directly above the top ends of the light emitting optical fiber and the light receiving optical fiber. Wherein the light emitting fiber and the light receiving fiber are applied as a multimode light emitting fiber and a multimode light receiving fiber, the multimode light emitting fiber uses a fiber of a core smaller than the multimode light receiving fiber, and the multimode light receiving fiber is a multimode fiber. The optical microphone which arrange | positions the optical fiber whose diameter of a core is large compared with the core of a light emitting optical fiber. In the manufacturing method of an optical microphone including a light emitting unit (LED) and a light emitting optical fiber, a light receiving optical fiber and a light receiving portion (PHOTODETECTOR), and a diaphragm for reflecting the light emitted from the light emitting optical fiber to the light receiving optical fiber, In order to apply the light emitting fiber and the light receiving optical fiber to the multimode light emitting fiber and the multimode light receiving fiber, the multimode light emitting fiber uses a fiber of a core smaller than the multimode light receiving fiber, and the multimode light receiving fiber is a multimode light emitting fiber. Selecting an optical fiber having a larger core diameter than the core; Bonding the selected multimode light emitting optical fiber and the multimode light receiving optical fiber to a fixing jig, the upper end of which protrudes out of the upper line of the fixing jig; Cutting the upper ends of the protruding multimode light emitting optical fiber and the multimode light receiving optical fiber along the upper line of the fixing jig; Method for producing an optical microphone, characterized in that consisting of.

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