KR101413159B1 - Optical microphone - Google Patents

Abstract

The present invention relates to an optical microphone which comprises an optical transmitting unit having a core of a first diameter with a total reflection surface; an optical receiving unit having a core of a second diameter which is larger than the first diameter; and a vibration plate to reflect the light output by the core of the first diameter and transmit the light to the core of the second diameter even if the vibration plate vibrates according to the intensity of external sound. Therefore, the present invention can increase a light reception level by using the sizes of the cores of the optical transmission unit and the optical receiving unit and improve the reception performance by using the modes of the optical transmission unit and the optical receiving unit.

Description

Optical Microphone {OPTICAL MICROPHONE}

BACKGROUND OF THE INVENTION 1. Field of the Invention [0002] The present invention relates to an optical microphone, and more particularly, to an optical microphone for enlarging an area of an optical signal that can be detected by a light microphone even in a swing of a diaphragm.

In general, optical microphones are based on optical conversion technology that converts mechanical acoustic signals into optical signals through optical fibers, and it does not cause any interference by surrounding electromagnetic fields or radiation, is excellent in sensitivity to sound pressure, It has excellent response characteristics and is recognized as a next generation technology that can replace existing condenser microphones. In addition, optical microphones can be divided into intensity modulation, phase modulation, and polarization modulation according to the optical modulation method used. In addition, the optical microphone can be applied to the smooth communication between the patient and the doctor without affecting the operation of the medical equipment system such as MRI (Magnetic Resonance Imaging) and CT (Computed Tomography). In addition, And can be effectively used to remotely monitor traffic and environment in places.

Korean Patent Laid-Open No. 10-2008-0016237 discloses an optical microphone related to the form of a first waveguide that emits light to a diaphragm and a second waveguide that collects the light reflected from the diaphragm. This optical microphone can increase the difference between the intensity of the light emitted from the light source and the intensity of the light transmitted to the light receiving element without increasing the angle of the upper surface of the waveguide, The range can be expanded.

Korean Patent Laid-Open No. 10-2008-0062084 discloses an optical microphone for reducing the area of the head portion of the optical microphone and providing ease of fabrication and a method of manufacturing the optical microphone. Such an optical microphone and its manufacturing method can diffract light toward the diaphragm by cutting an end surface of the optical fiber for light emission and light reception, which is a constitution of an optical microphone, into a fixing jig, The manufacturing cost can be reduced while greatly reducing the area of the head portion.

Conventional optical microphones have the same size of the optical transmission unit core and the same size of the optical reception unit core, so that the intensity of the optical signal generated due to the displacement of the diaphragm is lost, which causes a problem of performance degradation.

Korean Patent Publication No. 10-2008-0016237 Korean Patent Publication No. 10-2008-0062084

An embodiment of the present invention is to provide an optical microphone for enlarging an area of an optical signal that can be detected by a light microphone even in a swing of a diaphragm.

One embodiment of the present invention is to provide an optical microphone capable of increasing the light reception degree by increasing the size of the light receiving unit core than the size of the optical transmission unit core.

One embodiment of the present invention is to provide an optical microphone capable of providing a standard for the size of each of the cores of the optical transmitter and the optical receiver.

An embodiment of the present invention provides an optical microphone capable of presenting a reference according to modes of an optical transmitter and a light receiver.

In an embodiment, the optical microphone includes a light transmitting portion including a core of a first diameter having a total reflection surface, a light receiving portion including a core of a second diameter larger than the first diameter, And a diaphragm that reflects light output by the core of one diameter and transmits at least a part of the reflected light to the core of the second diameter.

In one embodiment, the optical transmitter and the optical receiver may further include a clad surrounding the cores of the first and second diameters and having the same diameters as each other. The input end of the light receiving unit may be formed in an oblique direction to increase the incident amount of the at least a part of the light. The incident angle of the light receiving unit with respect to the input end may be 15 to 30 degrees from the horizontal direction toward the light transmitting unit.

In one embodiment, the first and second diameters may be proportional to a first optical path length of the optical transmitter and the diaphragm, and a second optical path length of the optical receiver and the diaphragm. The first and second diameters may be set based on the maximum difference of the light reflection path by the diaphragm.

The first and second diameters may be designed through the following equations.

[Mathematical Expression]

C2 = f (Mdiff) * C1, and f (Mdiff) is a step function corresponding to the maximum difference of the light reflection path

The first and second diameters may be designed through the following equations.

[Mathematical Expression]

C2 = k2 * d2, C1 = k1 * d1, k1 and k2 are constants

In one embodiment, the core of the first diameter may be implemented in a single mode to transmit a single ray. In one embodiment, the core of the second diameter may be implemented in a multimode mode to transmit the at least a portion of the reflected light in multimode mode. The length of the optical path output from the core of the first diameter may be longer than the length of the optical path input to the core of the second diameter.

In embodiments, the optical microphone includes a diaphragm that vibrates according to the intensity of the external sound, an optical transmitter that transmits light to the diaphragm through a single mode core of a first diameter, And a light receiving unit that is capable of receiving light reflected by the diaphragm.

The optical microphone according to an embodiment of the present invention can increase the degree of optical reception using the core sizes of the optical transmitter and the optical receiver.

The optical microphone according to the embodiment of the present invention can improve the reception performance by using modes of the optical transmitter and the optical receiver.

1 is a block diagram illustrating an optical microphone according to an embodiment of the present invention.
2 is a block diagram illustrating the optical microphone of FIG.
Fig. 3 is a view for explaining the optical microphone shown in Fig. 1. Fig.
4 is a view illustrating an optical microphone according to another embodiment of the present invention.
5 is a view for explaining a light reflection path by vibration of the diaphragm shown in Fig.
FIG. 6 is a view for explaining an optical transmitter and a light receiver of the optical microphone according to another embodiment of FIG. 3;

The description of the present invention is merely an example for structural or functional explanation, and the scope of the present invention should not be construed as being limited by the embodiments described in the text. That is, the embodiments are to be construed as being variously embodied and having various forms, so that the scope of the present invention should be understood to include equivalents capable of realizing technical ideas. Also, the purpose or effect of the present invention should not be construed as limiting the scope of the present invention, since it does not mean that a specific embodiment should include all or only such effect.

Meanwhile, the meaning of the terms described in the present application should be understood as follows.

The terms "first "," second ", and the like are intended to distinguish one element from another, and the scope of the right should not be limited by these terms. For example, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component.

It is to be understood that when an element is referred to as being "connected" to another element, it may be directly connected to the other element, but there may be other elements in between. On the other hand, when an element is referred to as being "directly connected" to another element, it should be understood that there are no other elements in between. On the other hand, other expressions that describe the relationship between components, such as "between" and "between" or "neighboring to" and "directly adjacent to" should be interpreted as well.

It should be understood that the singular " include "or" have "are to be construed as including a stated feature, number, step, operation, component, It is to be understood that the combination is intended to specify that it does not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

In each step, the identification code (e.g., a, b, c, etc.) is used for convenience of explanation, the identification code does not describe the order of each step, Unless otherwise stated, it may occur differently from the stated order. That is, each step may occur in the same order as described, may be performed substantially concurrently, or may be performed in reverse order.

The present invention can be embodied as computer-readable code on a computer-readable recording medium, and the computer-readable recording medium includes all kinds of recording devices for storing data that can be read by a computer system . Examples of the computer-readable recording medium include a ROM, a RAM, a CD-ROM, a magnetic tape, a floppy disk, an optical data storage device, and the like, and also implemented in the form of a carrier wave (for example, transmission over the Internet) . In addition, the computer-readable recording medium may be distributed over network-connected computer systems so that computer readable codes can be stored and executed in a distributed manner.

All terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs, unless otherwise defined. Commonly used predefined terms should be interpreted to be consistent with the meanings in the context of the related art and can not be interpreted as having ideal or overly formal meaning unless explicitly defined in the present application.

FIG. 1 is a block diagram illustrating an optical microphone according to one embodiment of the present invention, FIG. 2 is a block diagram illustrating the optical microphone of FIG. 1, and FIG. 3 is a view illustrating the optical microphone of FIG. 1 .

1 to 3, the optical microphone 100 includes an optical transmitter 110, a light receiver 120, and a diaphragm 130.

The optical transmission unit 110 includes a core 111 having a first diameter and a first clad 112 surrounding the core 111 having a first diameter and the optical signal generated in the light source is transmitted to the diaphragm 130, . In one embodiment, the optical transmitter 110 may be implemented with an LED light source, a semiconductor laser light source, a vertical cavity surface emitting laser, or the like.

The core 111 of the first diameter can be realized by optical fibers (for example, glass) having a high refractive index and can be implemented as a total reflection surface to effectively reflect the optical signal generated in the light source.

The first diameter may be proportional to the first optical path length of the optical transmitter 110 and the diaphragm 130. In one embodiment, the first diameter may be implemented in proportion to the first optical path length of the optical transmitter 110 and the diaphragm 130, e.g., the first diameter may be implemented from 0.1 um to 10 um have.

In one embodiment, the first clad 112 may be implemented with optical fibers (e.g., glass) having a lower refractive index than the core 111 of the first diameter. This is because the light passing through the core 111 of the first diameter does not escape to the outside of the core 111 of the first diameter but causes total reflection only within the core 111 of the first diameter.

The optical receiving unit 120 includes a core 121 having a second diameter and a second clad 122 surrounding the core 121 having a second diameter. The optical receiving unit 120 receives the optical signal reflected from the diaphragm 130, Can be detected. Here, the second diameter may be larger than the first diameter.

The second diameter of the core 121 may be proportional to the second optical path length of the diaphragm 130. The second diameter of the core 121 may correspond to the length of the second optical path of the diaphragm 130. [ In one embodiment, the second diameter may be implemented in proportion to the second optical path length of the light receiving portion 120 and the diaphragm 130, for example, the second diameter may be implemented as 50 um to 100 um have.

The diaphragm 130 may be vibrated by the external sound, and the amplitude may vary depending on the intensity of the external sound. That is, the vibration of the diaphragm 130 increases as the intensity of the external sound increases, and the vibration decreases as the intensity of the external sound decreases. The diaphragm 130 can reflect at least part of the light output by the core 111 of the first diameter and transmit it to the core 121 of the second diameter even if it vibrates according to the intensity of the external sound.

More specifically, the diaphragm 130 reflects the optical signal output from the core 111 of the first diameter of the optical transmitter 110 when the intensity of the external sound is high, The number of optical signals detected by the optical receiver 120 may be reduced because the optical signals are widely scattered to the outside. The diaphragm 130 may reflect the light reflected from the diaphragm 130 when reflecting the optical signal output from the core 111 of the first diameter of the light transmitting unit 110 when the intensity of the external sound is low, The signal is not widely dispersed to the outside, so that the optical signal detected by the optical receiver 120 can be increased.

In one embodiment, the thickness of the diaphragm 130 may correspond to about 0.1 um to about 10 um so as to shake the external fine sound pressure. In one embodiment, the diaphragm 130 may be embodied as a metal (e.g., gold, silver, aluminum, copper, nickel, etc.) or coated with a metal so as to have a high reflectivity.

The diaphragm 130 vibrates according to the intensity of the external sound to reflect the optical signal transmitted from the optical transmitter 110 and the optical reflection path received by the optical receiver 120 varies according to the amplitude of the diaphragm 130 .

4 is a view for explaining an optical microphone according to another embodiment of the present invention.

Referring to FIG. 4, the optical microphone 100 includes an optical transmitter 110, a light receiver 220, and a diaphragm 130. Here, since the optical transmitting unit 110 and the diaphragm 130 are illustrated in FIG. 3, description thereof will be omitted and the structure of the optical receiver 220 will be mainly described.

The input end of the light receiving unit 220 may be formed in a slant line to increase the amount of incident light of at least a part of the light. Accordingly, the core 221 of the second diameter and the second clad 222 may also be formed in a diagonal line.

The input end of the light receiving unit 220 may be diagonally opposed to the diaphragm 130 and the cores 221 of the second diameter formed by diagonal lines may be broadened and reflected by the diaphragm 130 The incident amount of light can be increased.

In one embodiment, the vibration of the diaphragm 130 does not occur in the absence of external sound, so that the incident amount of light reflected from the diaphragm 130 to the light receiving unit 220 may increase. In the presence of external sound, The vibration of the diaphragm 130 is changed to change the position of the diaphragm 130 and the incident amount of the light reflected from the diaphragm 130 to the light receiving unit 220 may be reduced.

That is, the diaphragm 130 may affect the incident amount of the light reflected from the diaphragm 130 to the light receiving unit 220 according to the external sound.

The incident angle with respect to the input end of the light receiving unit 220 can be 15 to 30 degrees from the horizontal direction to the light transmitting unit 110. The second diameter increases as the incident angle is formed, The incident amount can be increased.

5 is a view for explaining a light reflection path by vibration of the diaphragm shown in Fig.

Referring to FIG. 5, the optical microphone 100 includes an optical transmitter 110, a light receiver 120, and a diaphragm 130. Here, since the optical transmitter 110, the optical receiver 120, and the diaphragm 130 are shown in FIG. 3, description thereof will be omitted and a change in the optical signal path will be mainly described.

The core 111 of the first diameter and the cores 121 of the second diameter can be set based on the maximum difference of the light reflection path by the diaphragm 130. [

Depending on the external sound, the diaphragm 130 may vibrate between a and the core 111 of the first diameter may transmit the optical signal to the diaphragm 130 in the b path. When the diaphragm 130 does not vibrate, the optical signal of the b path transmitted from the core 111 of the first diameter can be received by the d path to the core 121 of the second diameter.

When the diaphragm 130 vibrates between a and b, the optical signal of the b path transmitted from the core 111 of the first diameter at the time when the diaphragm 130 is farthest from the optical transmitter 110 and the optical receiver 120 And is transmitted to the core 121 of the second diameter by an e path and transmitted from the core 111 of the first diameter at the time when the diaphragm 130 is closest to the optical transmitter 110 and the optical receiver 120 the optical signal of path b can be received by the path c to the core 121 of the second diameter.

The core 111 of the first diameter and the cores 121 of the second diameter may be designed through the following equations.

[Mathematical Expression]

C2 = f (Mdiff) * C1

Here, C1 is the stepped function of the core 111 of the first diameter, C2 is the core 121 of the second diameter, and f (Mdiff) is the step function corresponding to the maximum difference in the light reflection path.

The core 121 of the second diameter may be equal to a value multiplied by a step function corresponding to the maximum difference in the optical reflector when transmitting the core 111 of the first diameter and the diaphragm 130 in the optical transmitter 110.

The core 111 of the first diameter and the cores 121 of the second diameter may be designed through the following equations.

[Mathematical Expression]

C2 = k2 * d2, C1 = k1 * d1 where C1 is a core of a first diameter 111, C2 is a core of a second diameter 121, and k1 and k2 are constants.

The core 111 having the first diameter may be proportional to the value obtained by multiplying the first optical length d1 of the optical transmitting unit 110 and the diaphragm 130 by the constant k1, And may be proportional to a value obtained by multiplying the second light length d2 of the light receiving unit 120 and the diaphragm 130 by a constant k2.

In one embodiment, the core 121 of the second diameter may transmit the optical signal b at a distance of the first optical length (d1) to the diaphragm 130 that vibrates between a.

The second diameter is the distance from the diaphragm 130 to the diaphragm 130 and the optical transceivers 110 and 120 that are closest to the diaphragm 130 and the optical transceivers 110 and 120, The optical signal received by the light receiving unit 120 at the time point of the c-path can be designed.

FIG. 6 is a view for explaining an optical transmitter and a light receiver of the optical microphone according to another embodiment of FIG. 3;

Referring to FIGS. 6A and 6B, the optical microphone 100 includes an optical transmitter 110 and a light receiver 120. 3, the optical transmission unit 110 and the optical reception unit 120 are omitted from the description, and the optical transmission unit 110 and the optical reception unit 120 are connected to the core 111 of the first diameter of the optical transmission unit 110 and the second Diameter core 121 will be mainly described.

The first diameter core 111 may be implemented in a single mode to transmit a single light beam. The width of the core 111 of the first diameter may correspond to several millimeters (for example, 5 um to 10 um).

The core 111 of the first diameter is narrow in diameter and can reflect a single optical signal to the diaphragm 130.

The second diameter core 121 may be implemented in a multimode mode to transmit at least some of the reflected light in multimode mode. The width of the core 121 of the second diameter may correspond to the number of the core 121 of the first diameter beforehand (for example, 50 um to 100 um).

The core 121 of the second diameter can receive a large amount of reflected light reflected by the diaphragm 130 because of its large diameter. The length of the optical path output from the core 111 of the first diameter may be longer than the length of the optical path input to the core 121 of the second diameter.

 The core 111 of the first diameter may transmit a single optical signal generated in the light source to the diaphragm 130 in a linear waveform and the core 121 of the second diameter may transmit the optical signal reflected from the diaphragm 130 And transmit it to the optical detecting section with a waveform of a curve.

In an embodiment, the diaphragm 130 may vibrate according to the intensity of the external sound, and the diaphragm 130 may reflect the optical signal transmitted from the optical transmitter 110 and receive the optical signal by the optical receiver 120. The optical transmitter 110 may transmit light to the diaphragm 130 through the single mode core of the first diameter and the optical receiver 120 may be transmitted by the optical transmitter 110 through the multimode core of the second diameter And can receive the light reflected by the diaphragm 130.

Hereinafter, the operation of the optical microphone according to one embodiment of the present invention will be described in detail.

The diaphragm 130 can vibrate according to the external sound, and the diaphragm 130 can be vibrated even with a slight external sound, so that the light receiving unit 120 is effective in detecting the optical signal.

The optical transmitter 110 transmits an optical signal to one surface of the diaphragm 130 when the diaphragm 130 vibrates due to an external sound so that the optical receiver 120 can detect the vibration of the diaphragm 130. [

The vibration of the diaphragm 130 becomes stronger as the intensity of the external sound is increased and a difference in the light reflection path occurs when the optical signal is reflected from the diaphragm 130 to the light receiving unit 120.

The size of the second diameter of the light receiving unit 120 may be increased to minimize the loss due to the difference in the light reflection path and the input end of the light receiving unit 120 may be formed in a diagonal line to increase the incident rate of the optical signal. .

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the present invention as defined by the following claims It can be understood that

100: Optical microphone
110: Optical transmitter
111: first diameter
112: first clad
120, and 220:
121, 221: second diameter
122, 222: a second clad
130: diaphragm

Claims (12)

A core having a first diameter and having a total reflection surface and being implemented in a single mode and transmitting a single light beam having a straight line waveform, the optical fiber wrapping the core having the first diameter and having a refractive index lower than that of the core having the first diameter A first clad disposed on the first clad;
A light receiving portion including a second diameter core having a waveform of a curved line, the second diameter being larger than the first diameter and being implemented in a multimode mode, and a second cladding surrounding the core of the second diameter; And
And a diaphragm which reflects the light output by the core of the first diameter and transmits at least a part of the reflected light to the core of the second diameter even if it vibrates according to the intensity of the external sound.
delete The optical receiver according to claim 1,
Wherein the light source is formed in a diagonal line to increase an incident amount of the at least a part of the light.
4. The apparatus of claim 3, wherein the incident angle to the input of the light receiving unit
And 15 to 30 degrees in a direction from the horizontal to the optical transmission unit.
2. The method of claim 1, wherein the first and second diameters
The first optical path length of the optical transmitter and the diaphragm, and the second optical path length of the optical receiver and the diaphragm, respectively.
4. The method of claim 3, wherein the first and second diameters
And a maximum difference of a light reflection path by the diaphragm.
7. The method of claim 6, wherein the first and second diameters
And is designed through the following equation.

[Mathematical Expression]
C2 = f (Mdiff) * C1, and f (Mdiff) is a step function corresponding to the maximum difference of the light reflection path
8. The method of claim 7, wherein the first and second diameters
And is designed through the following equation.

[Mathematical Expression]
C2 = k2 * d2, C1 = k1 * d1, k1 and k2 are constants
delete delete The optical fiber according to claim 1, wherein the length of the optical path output from the core of the first diameter is
And the length of the optical path input to the core of the second diameter is longer than the length of the optical path input to the core of the second diameter.
delete

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