JPH0139280B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a microphone, and an object of the present invention is to provide a small, lightweight microphone with high reproduction fidelity that can directly convert changes in the amplitude range of a diaphragm into changes in the intensity of light. It is.

An embodiment of the invention is shown in FIGS. 1 and 2. That is, this microphone has a circular diaphragm 1 made of a translucent material such as methacrylic resin and whose periphery is fixed, and has a linear region from a part of the periphery to the center that has a refractive index larger than other regions. The boundary between the high refractive canonical region and other regions at the end of the circular diaphragm center side is set at a predetermined inclination angle with respect to the surface of the circular diaphragm to form a light reflecting surface 2a, and this high refractive canonical region The light guide path is a light guide path 2, and a light source 3 is arranged at a position opposite to the end of the light guide path 2 on the peripheral edge side of the circular diaphragm.
The circular vibrating membrane 1 allows the light projected onto the light guide path 2 to be reflected from the light reflecting surface 2a and radiated.
The light reflecting surface 2a is located near the center of one side of the
A photoelectric conversion element 4, such as a phototransistor, is provided to receive reflected light from the mirror and convert it into an electrical signal.

The operation of this microphone will be described next.

Since the light guide path 2 consisting of the high refractive straight line area has a higher refractive index than other areas of the circular diaphragm 1, light is projected into the light guide path 2 from the light source 3 as shown in FIG. The light is reflected at the interface with other areas of the light guide path 2, and similarly, as shown in FIG.
The light propagates toward the center of the circular diaphragm 1 while being reflected at the interface with the material (lower than the material of the
It is reflected and radiated to the back side of the circular vibrating membrane 1.
The emitted light is received by the photoelectric conversion element 4 and outputs an electric signal corresponding to the amount of received light.

On the other hand, since the circular diaphragm 1 vibrates in response to the sound pressure P, the light reflecting surface 2a of the light guide path 2 located at the center of the circular diaphragm 1 having a large amplitude is affected by the vibration of the circular diaphragm 1. The angle with respect to the photoelectric conversion element 4, which does not exist, varies greatly. And circular vibrating membrane 1
As the amplitude increases, the light emitted from the light reflecting surface 2a deviates from the photoelectric conversion element 4, so the amount of light received by the photoelectric conversion element 4 decreases accordingly, and conversely, as the amplitude decreases, the amount of light received increases, causing photoelectric conversion. The electrical signal output from the conversion element 4 is proportional to the vibration of the circular vibrating membrane 1.

With this configuration, the following effects can be obtained.

(1) The vibration of the circular diaphragm 1 can be directly converted into light intensity, resulting in a microphone with high reproduction fidelity.

(2) By making a part of the circular diaphragm 1 have a high refractive index,
Since this is used as the light guide path 2, the light guide path 2 is integrated with the circular diaphragm 1, and the reproduction fidelity can be further improved without causing an increase in mass, and the overall shape can be made smaller. .

(3) Also, the light emitted into the light guide path 2 is
Instead of directly arranging the light source 3 at the edge of the circular diaphragm periphery, an optical fiber is used, and similarly, instead of directly receiving the light emitted from the light guide path 2 by the photoelectric conversion element 4, an optical fiber is used. The light source 3 and the photoelectric conversion element 4 are
The electrical wiring of the microphone can be separated from the main part including the circular diaphragm 1 of the microphone, making it possible to extend it over a long distance.

Failures caused by poor wiring connections can be reduced.

Improves noise resistance.

Safety (especially explosion-proofness) is improved.

It becomes possible to make it smaller and lighter.

Benefits such as:

Other embodiments of the invention are shown in FIGS. 5-7. That is, in this microphone, a reflection mirror 6 is installed in place of the photoelectric conversion element 4 in the position of the photoelectric conversion element 4 in the above embodiment, and the reflection mirror 6 is placed opposite to the light guide path 2 of the circular vibrating membrane 1'. Similar to the light guide path 2, the refractive index of the linear region from a part of the periphery to the center is determined by the circular vibrating membrane 1'.
The boundary between the second high refractive straight line area and the other area on the central side of the circular diaphragm is set so that the light emitted from the light reflecting surface 2a of the light guide path 2 is made larger than the other area, and the reflection mirror 6 is set at a predetermined inclination angle that allows the light to be incident thereon, and this second high-refraction canonical line area is used as a light guide path 7 for condensing light. A photoelectric conversion element 4' is arranged at a position facing the peripheral edge of a circular vibrating membrane, and the other configurations are the same as those of the previous embodiment.

FIG. 7 shows that, as described in the previous embodiment, the light source 3 and the photoelectric conversion element 4' are not placed directly in the vicinity of the circular diaphragm 1', but emit and receive light via optical fibers 8 and 9. This figure shows a modified example.

In this microphone, the light emitted from the light reflecting surface 2a of the light guide path 2 is directly transmitted to the photoelectric conversion element 4'.
Rather than being received by the reflection mirror 6, the reflected light enters the condensing light guide path 7 from the light incidence surface 7a and reaches the end of the condensing light guide path 7 on the circular vibrating membrane peripheral side. It is then received by the photoelectric conversion element 4' for the first time and converted into an electrical signal.
Therefore, when the amplitude of the circular diaphragm 1' is large,
The amount of light emitted from the light reflecting surface 2a of the light guide path 2 received by the reflecting mirror 6 decreases, and
The incidence ratio of light from this reflection mirror 6 to the light incident surface 7a of the light guide path 7 for condensing is further reduced than when the amplitude is small, and the light that is condensed through the light guide path 7 for condensing is circular. The intensity change accompanying the vibration of the vibrating membrane 1' is further amplified.

With this configuration, sensitivity is increased and reproduction fidelity is further improved. Other effects are the same as in the previous embodiment.

As described above, the microphone of the present invention is formed from a diaphragm and a fixed part of the diaphragm to a large amplitude region, and propagates incident light from the fixed part side toward the surface of the diaphragm from the large amplitude region side. a light guide that emits light from the large amplitude area side of the light guide, a light source that is provided at a position opposite to the fixed part side of the light guide and projects light into the light guide, and a light source that emits light from the large amplitude region side of the light guide onto the surface of the diaphragm. Since it is equipped with a photoelectric conversion means that converts the change in the amount of received light caused by the vibration of the diaphragm into an electrical signal at a nearby predetermined position, it is possible to reduce the size and weight and improve the reproduction fidelity. Further, the microphone of the present invention includes a diaphragm, and a structure formed from a first fixed part of the diaphragm to a large amplitude region, and propagates incident light from the first fixed part side toward the surface of the diaphragm from the large amplitude region side. a first light guide path that emits light;
a light source provided at a position facing the first fixed part side of the first light guide path and projecting light into the first light guide path; and a light source that emits light from the large amplitude region side of the first light guide path close to the surface of the diaphragm. a reflective mirror that receives at a predetermined position and reflects an amount of light proportional to the amount of received light that changes with the vibration of the diaphragm; a second light guide path that receives light on the area side and propagates to the second fixing part side; and a photoelectric conversion means that receives emitted light from the second fixing part side of the second light guide path and converts a change in the amount of received light into an electrical signal. As a result, the rate of change in the amount of light received by the photoelectric conversion means due to the vibration of the diaphragm is further increased, and reproduction fidelity is further improved.

[Brief explanation of drawings]

FIG. 1 is a side view showing an embodiment of the present invention, FIG. 2 is a perspective view thereof, and FIGS. 3 and 4 are a plan view and a side view of a main part showing its operation, respectively.
FIG. 5 is a side view showing another embodiment of the invention, FIG. 6 is a perspective view thereof, and FIG. 7 is a side view showing a modification thereof. 1, 1'...Circular diaphragm (diaphragm), 2...Light guide path,
2a...Light reflecting surface, 3...Light source, 4, 4'...Photoelectric conversion element, 6...Reflecting mirror, 7... Light guide path for condensing light, 7a
...Light incidence surface.

Claims (1)

[Scope of Claims] 1. A diaphragm, and a guide formed from a fixed part of the diaphragm to a large amplitude region, which propagates incident light from the fixed part side and radiates it from the large amplitude region side toward the surface of the diaphragm. a light path, a light source provided at a position facing the fixed part side of the light guide and projecting light into the light guide, and a light source emitted from the large amplitude region side of the light guide at a predetermined position close to the surface of the diaphragm. A microphone comprising photoelectric conversion means for converting changes in the amount of received light caused by vibrations of the diaphragm into an electrical signal. 2. The diaphragm is a circular film made of a translucent material and has a fixed periphery, and the light guide path extends from a part of the periphery of the circular film, which is set to have a higher refractive index than other areas, to a central part. The boundary between the circular film center side of the high refractive canonical region and the other low refractive index region is a light reflecting surface that forms a predetermined inclination angle with respect to the circular film surface. , the photoelectric conversion means is a photoelectric conversion element provided at a predetermined position close to a circular film surface capable of receiving reflected light from the light reflecting surface of the light guide path formed in the high refractive straight line area. A microphone according to scope 1. 3. A diaphragm, and a first light guide path formed from a first fixed part of the diaphragm to a large amplitude region, which propagates incident light from the first fixed part side and radiates it toward the surface of the diaphragm from the large amplitude region side. a light source provided at a position facing the first fixed part side of the first light guide path and projecting light into the first light guide path, and a light source that emits light from the large amplitude region side of the first light guide path to the diaphragm surface. a reflecting mirror that receives light at a predetermined position close to the diaphragm and reflects an amount of light proportional to the amount of received light that changes as the vibration of the diaphragm; 2nd receiving on large amplitude area side
A microphone comprising: a second light guide path that propagates toward a fixed part; and a photoelectric conversion means that receives emitted light from the second fixed part side of the second light guide path and converts a change in the amount of received light into an electrical signal. 4. The diaphragm is a circular film made of a translucent material and has a fixed periphery, and the first light guide path extends from a part of the periphery of the circular film that is set to have a higher refractive index than other areas. Consisting of a first high refractive straight line region extending toward the center, the boundary between the first high refractive straight line region on the circular film center side and the other low refractive index region forms a predetermined inclination angle with respect to the circular film surface. The reflection mirror is provided at a predetermined position close to a circular film surface capable of receiving reflected light from the light reflection surface of the first light guide path, and The optical path includes a second high refractive straight line region from the other part of the peripheral edge of the circular film to the center part, which is set to have a higher refractive index than the other part region with a low refractive index and is opposite to the first light guide path. The boundary between the circular film center side of the second high refractive straight line area and the other low refractive index area is a light incident surface forming a predetermined inclination angle that can receive the reflected light from the reflecting mirror. , the photoelectric conversion means is a photoelectric conversion element that is provided at a position facing the circular film peripheral side of the second light guide path and receives and photoelectrically converts the emitted light from the second light guide path. Microphone according to item 3.