JP3955276B2 - Microphone unit and its mounting structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a microphone unit using a microphone that detects sound and converts it as an electrical signal, and a mounting structure thereof.
[0002]
[Prior art]
A microphone detects sound and converts it into an electrical signal. Generally, this microphone is mounted on a printed wiring board together with an electric circuit that amplifies the signal from the microphone as a microphone unit, and the printed wiring board is further connected to a sound hole. It is often used as a microphone unit that is housed in a housing with This is because the electrical output from the microphone is small and this signal is pulled out as it is and connected to an external device, so that external electrical noise enters the connection line and the SN ratio cannot be secured. This is because it is necessary to guide the signal to the outside after creating a large signal. FIG. 5 is a structural cross-sectional view of a general microphone unit 113 having such a configuration.
[0003]
Reference numeral 101 denotes a printed wiring board on which a microphone 102 for detecting sound is mounted. In addition, an electrical component 103 for amplifying an electrical signal from the microphone 102 is mounted on the printed wiring board 101. The printed wiring board 101 is disposed inside a space formed by an upper housing 105 and a lower housing 106 each having a sound hole 104 for taking in sound, and is protected from external blows and the like. It is attached to a predetermined position through. Generally, the upper housing 105 and the lower housing 106 are formed by a resin molded product, a metal press work, or the like. Reference numeral 107 denotes a connection line for extracting a signal from the microphone unit 113 to the outside and supplying power for operating an internal electric circuit. The printed wiring board 101 is connected to the upper casing 105 in this case. It is pulled out through the hole 108. In the case of the microphone unit 113 having such a structure, the inner space of the upper and lower casings 105 and 106 where the microphone 102 exists and the external space are centered on the sound hole 104 of the upper casing 105, but the upper casing In reality, although there is a slight gap in the insertion portion between the through hole 108 and the connection line 107 for passing the connection line 107 opened in the fitting part 109 of the lower case 106 and the upper case 105 and the connection line 107. There is also a slight spatial connection here.
[0004]
In addition, the microphone unit is not mounted on the printed circuit board, but the microphone is held inside an elastic folder such as rubber, and the elastic folder holding the microphone is fixed to an external housing having a sound hole, and the output line of the microphone Is connected to the printed wiring board.
[0005]
As prior art document information related to the invention of this application, for example, Patent Document 1 is known.
[0006]
[Patent Document 1]
Japanese Patent No. 2960220
[Problems to be solved by the invention]
FIG. 6 is a schematic diagram of a case in which the sound of one of the two sealed spaces separated by the partition plate is detected by installing the microphone unit 113 shown in FIG. 5 on the other space side of the partition plate. . Reference numeral 110 denotes a partition plate, which creates two sealed spaces, a measured space 111 and a microphone unit installation side space 112.
[0008]
The microphone unit 113 is installed in the microphone unit installation side space 112 so as to detect sound in the space to be measured 111 through the sound hole 114 vacated in the partition plate 110.
[0009]
When considering such a case, when the dimension of the sealed space is sufficiently larger than the wavelength of the sound wave to be measured, the sound of the microphone unit installation side space 112 in which the microphone unit 113 is arranged is shown in FIG. The microphone 102 passes through the fitting portion 109 between the upper housing 105 and the lower housing 106 of the microphone unit 113 and the gap between the insertion portion between the through hole 108 and the connection wire 107 for passing the connection wire 107 opened in the upper housing 105. The amount of leakage into the interior surrounded by the upper and lower casings 105 and 106 where the noise exists is very small, and the sound to be measured substantially passes through the sound hole 114 of the partition plate 110 through the sound hole 114 of the partition plate 110. Only the sound pressure generated in the unit 113 is present and no problem occurs.
[0010]
However, in a region where the dimension of the sealed space is equal to or less than the wavelength of the sound wave to be measured, that is, when measuring a very low frequency sound, the microphone unit installation side space where the microphone unit 113 is installed. Based on Pascal's principle, the sound pressure of the very low frequency 112 is a connection line opened in the upper casing 105 and the fitting section 109 of the lower casing 106 and the upper casing 105 of the microphone unit shown in FIG. The sound pressure in the microphone unit installation-side space 112 is almost equal to the inside surrounded by the upper and lower casings 105 and 106 where the microphone 102 exists through the gap between the insertion hole between the through-hole 108 and the connection line 107 for passing the 107. The same sound pressure is generated inside the housing of the microphone unit 113.
[0011]
Therefore, at a very low frequency, there is a problem that what should originally detect the sound in the measured space 111 detects even the sound in the microphone unit installation side space 112. Such a case occurs, for example, when a sound on the passenger compartment side near the rear tray of the vehicle is detected. The vehicle is divided into two sealed spaces, a vehicle compartment and a trunk, by a rear tray, and the microphone unit may be installed on the trunk side due to the design restrictions of the vehicle compartment.
[0012]
Also, the microphone unit shown in the conventional example is not mounted on the printed circuit board, but the microphone is held inside an elastic folder such as rubber, and the elastic folder holding the microphone is fixed to an external housing having a sound hole. In some cases, the output line of the microphone is connected to the printed wiring board (see, for example, Patent Document 1). In this case, the elastic folder comes into close contact with the housing having the sound holes, and the sound Leakage does not occur, but the microphone is not mounted on the printed wiring board, and the output line from the microphone must be soldered later. Therefore, there are problems such as an increase in cost.
[0013]
The purpose of the present invention is to realize a structure in which the sound detected by the microphone present in the microphone unit as shown in FIG. 5 is only the sound from the sound hole of the upper housing by an inexpensive method. To do.
[0014]
[Means for Solving the Problems]
In order to achieve the above object, the present invention has the following configuration.
[0015]
Invention of Claim 1 of this invention is a printed wiring board, the microphone mounted in this printed wiring board, the housing | casing which has a sound hole for taking in a sound while the said printed wiring board is stored, A microphone unit including a microphone mounted on a printed wiring board in a non-contact state and connected between the printed wiring board and a sound hole peripheral portion of the housing by a pipe-shaped structure , the pipe-shaped A flexible material is joined to one end face of the main body portion made of a hard material of the structure, and the connection is substantially made by compressing the flexible material.
[0016]
According to the above-described invention, it has the effect that only sound through the sound hole of the housing can be detected accurately even when detecting sound of a very low frequency, and the dimensional accuracy of the hollow cylindrical structure is not so high. Good connection is possible even in the state, and only the sound through the sound hole of the housing can be detected accurately even in the detection of a very low frequency sound.
[0017]
The invention according to claim 2 of the present invention is an invention for a structure practically attached to the plate-like structure of the microphone unit according to claim 1 of the present invention, a printed wiring board, the printed wiring board The printed wiring board including a microphone to be mounted, a casing in which the printed wiring board is housed and having a sound hole for taking sound therein, and a microphone mounted on the printed wiring board in a non-contact state inside A microphone unit having a structure in which the first pipe-shaped structure is connected between the sound hole and the sound hole surrounding portion of the housing is provided on one surface of the plate-shaped structure having a sound hole to which the microphone unit is to be attached. Each sound hole is arranged together, and a decorative board having sound holes is placed on the other surface of the plate-like structure to which the microphone unit is to be attached. A microphone unit which is connected a sound hole and the veneer sound hole of the microphone unit in the second pipe-like structures with are arranged together a sound hole as said second to said veneer A pipe-like structure is integrally formed, and a second boss-like structure is formed around the sound hole of the microphone unit by fastening a mounting boss provided on the decorative plate and a lower portion of the housing with screws. It is configured to be closely connected to the part. And according to this invention, it has the effect | action that only the sound which passed through the sound hole of the decorative board can be detected correctly also in the sound of a very low frequency.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Prior to describing the invention according to claim 1 relating to the microphone unit, a reference example of the present invention will be described.
[0019]
FIG. 1 is a sectional view showing a structure of a microphone unit according to a reference example of the present invention. Reference numeral 115 denotes a printed wiring board, and reference numeral 116 denotes a microphone mounted on the printed wiring board 115. Similarly, 117 is a simplified representation of the electronic components mounted on the printed wiring board 115 and amplifies the signal of the microphone 116.
[0020]
Reference numeral 119 denotes an upper housing having a sound hole 118, and 120 denotes a lower housing. A printed wiring board 115 is disposed in an internal space formed by the upper casing 119 and the lower casing 120. Reference numeral 121 denotes a connection line that is connected to the printed circuit board 115 to draw a signal to the outside or supply power, and is drawn to the outside through the through hole 122 of the upper casing 119. Reference numeral 123 denotes a gap at the joint between the upper housing 119 and the lower housing 120. Reference numeral 124 denotes a pipe-like structure that includes a sound hole 118 and a microphone 116 opened in the upper housing 119 and connects the upper housing 119 and the printed wiring board 115.
[0021]
With such a structure, the microphone 116 is connected to the external space only through the inside of the pipe-like structure 124 through the sound hole 118 opened in the upper housing 119, and the upper housing 119 and the lower housing are connected. The sound from the gap 123 at the joint portion of the body 120 and the gap between the through hole 122 and the connection line 121 of the upper housing 119 is eliminated, and the sound from the sound hole 118 accurately opened in the upper housing 119 by the microphone 116 is eliminated. Can only detect.
[0022]
Hereinafter, an embodiment of the invention described in claim 1 of the present invention will be described.
[0023]
In FIG. 2 , reference numeral 125 denotes a printed wiring board, and 126 denotes a microphone mounted on the printed wiring board 125. Similarly, 127 represents an electronic component mounted on the printed wiring board 125, and amplifies the signal of the microphone 126. Reference numeral 129 denotes an upper casing having a sound hole 128, and reference numeral 130 denotes a lower casing. A printed wiring board 125 is disposed in an internal space formed by the upper casing 129 and the lower casing 130. Reference numeral 131 denotes a connection line that is connected to the printed circuit board 125 to draw a signal to the outside or supply power, and is drawn to the outside through the through hole 132 of the upper housing 129. Reference numeral 133 denotes a gap at the joint between the upper housing 129 and the lower housing 130. Reference numeral 134a denotes a main body portion of a pipe-like structure 134 that includes a sound hole 128 opened in the upper housing 129 and a microphone 126, and connects the upper housing 129 and the printed wiring board 125. Made of hard material. Reference numeral 134b denotes a tip portion made of a structurally flexible material joined to the upper end of the main body portion 134a of the pipe-like structure 134. The main body portion 134a and the distal end portion 134b form a pipe-like structure 134 that connects the upper housing 129 and the printed wiring board 125.
[0024]
This sound is detected by the microphone 126 cases become only those from the sound hole 128 bored in the upper housing 129 is similar to the reference example, in the case of the form status of the embodiment shown in FIG. 2 FIG. It is necessary to ensure the connection by precisely matching the dimension of the pipe-like structure 124 that connects the upper casing 119 and the printed wiring board 115 to the dimension between the upper casing 119 and the printed wiring board 115. Therefore it is necessary to very high dimensional accuracy of the microphone unit each part, but if the form status of implementation pipe-like structure 134 for connecting the upper housing 129 and the printed wiring board 125 of FIG. 2 is a hard material The pipe-shaped structure 134 has a dimension larger than the dimension between the upper housing 129 and the printed wiring board 125. The body 134a is composed of a main body 134a and a tip 134b made of a flexible material. In addition, there is an advantage that strict joining can be performed by compressing a portion made of a flexible material of the pipe-like structure 134, and it is not necessary to increase the dimensional accuracy of each part of the microphone unit.
[0025]
Prior to describing the invention according to claim 2 relating to the microphone unit, a reference example of the present invention will be described.
[0026]
FIG. 3 is a cross-sectional view of a microphone unit mounting structure according to a reference example of the present invention. 136 is a microphone unit shown in FIG. 1 provided with the first pipe-like structure 124, and 118 is a sound hole of the microphone unit 136. Reference numeral 138 denotes a plate-like structure to which the microphone unit 136 is to be attached, and a sound hole 139 is opened. Reference numeral 140 denotes a plate-like decorative board arranged on the opposite side of the plate-like structure 138 where the microphone unit 136 is arranged, and the sound hole 141 is similarly opened.
[0027]
As can be seen from FIG. 3, the sound hole 118 of the microphone unit 136, the sound hole 139 of the plate-like structure board 138, and the sound hole 141 of the decorative board 140 are arranged on a straight line. Reference numeral 142 denotes a second pipe-like structure, which connects the decorative plate 140 and the upper surface of the microphone unit 136 so as to include the sound holes 141 and 139 therein. Reference numeral 143 denotes a gap generated between the microphone unit 136 and the plate-like structure 138. If there is no second pipe-like structure 142, sound on the microphone unit 136 side passes through the gap 143 and enters the microphone unit 136. It seems easy to understand getting in.
[0028]
In this way, by adopting the above-described mounting structure, it is possible to accurately detect only the sound in the targeted space even when the actual microphone unit is considered.
[0029]
Next, an embodiment of the invention described in claim 2 of the present invention will be described.
[0030]
FIG. 4 shows an embodiment of the present invention when it is attached to a partition plate provided at the boundary between two sealed spaces and only the sound of one space is detected.
[0031]
Reference numeral 144 denotes a partition plate provided at the boundary of the sealed space, which is divided into two sealed spaces, a sound measurement space 145 and a space 146 in which the microphone unit 147 is disposed. The microphone unit 147 has a printed wiring board 148 mounted with a microphone 149 and an electric component 150 installed in an internal space composed of an upper housing 151 and a lower housing 153 having sound holes 152. An upper housing 151 and a printed wiring board 148 are connected by a first pipe-shaped structure 159 so as to include an opened sound hole 152 and a microphone 149 therein. Reference numeral 154 denotes a connection line drawn out from the printed wiring board 148 to the outside through a through hole 155 opened in the upper casing 151. Reference numeral 160 denotes a decorative plate arranged on the measured space 145 side, and has a sound hole 161 at the center.
[0032]
The decorative board 160 has a second pipe-like structure 162 on the microphone unit 147 side so as to include the sound hole 161 on the inside, and the mounting boss 163 and the microphone unit 147 provided on the decorative board 160 are also provided. By tightening the lower casing 153 with screws 164, the pipe-shaped structure 162 is closely connected so that the upper casing 151 of the microphone unit 147 and the sound hole 152 opened in the upper casing 151 are included therein. It is supposed to be.
[0033]
At this time, considering a route in which the sound of the space 146 in which the microphone unit 147 is disposed reaches the microphone 149 of the microphone unit 147, the gap 156 between the fitting portions of the upper housing 151 and the lower housing 153 of the microphone unit 147, Sound enters the microphone unit 147 through the gap 157 between the connection line 154 and the through-hole 155, but is blocked by the first pipe-shaped structure 159, so the sound in this path is not detected by the microphone 149.
[0034]
On the other hand, the sound from the gap 158 between the upper housing 151 of the microphone unit 147 and the partition plate 144 is also closely connected to the second pipe structure 162 provided on the decorative plate 160 and the upper housing 151 of the microphone unit 147. Therefore, it is not detected by the microphone 149. Accordingly, the sound in the space 146 in which the microphone unit 147 is installed is not detected at all, and only the sound in the measured space 145 is the sound hole 161 of the decorative plate 160 and the sound hole 152 of the upper housing 151 of the microphone unit 147. And reaches the microphone 149 to be detected.
[0035]
【The invention's effect】
As described above, according to the present invention, there is no need to install a microphone unit inside the measured sealed space in order to accurately detect low-frequency sound only in a certain sealed space, and the microphone outside the measured sealed space. Even if the unit is installed, it is possible to accurately detect the low frequency sound only in the sealed space to be measured, and an advantageous effect is obtained that it can be used even in places where design restrictions are large.
[Brief description of the drawings]
[1] of the microphone unit according to a reference example of reference structural cross-sectional view of the microphone unit according to the example structural cross-sectional view of the microphone unit according to the shape condition of the embodiment of the present invention; Fig 3 shows the invention of the present invention 4 is a cross-sectional view of a mounting structure of a microphone unit according to an embodiment of the present invention. FIG. 5 is a cross-sectional view of a structure of a conventional microphone unit . Schematic diagram of mounting structure in case [Explanation of symbols]
115, 125, 148 Printed wiring board 116, 126, 149 Microphone 117, 127, 150 Electrical component 118, 128, 139, 141, 152, 161 Sound hole 119, 129, 151 Upper housing 120, 130, 153 Lower housing 121, 131, 154 Connecting line 122, 132, 155 Through hole 123, 133, 143, 156, 157, 158 Gap 144 Partition plate 145 Measurement space 146 Microphone unit installation space 136, 147 Microphone unit 124, 134, 142, 159 , 162 Pipe-shaped structure 138 Plate-shaped structure 140, 160 Decorative plate 163 Mounting boss 164 Screw

Claims (2)

A printed wiring board, a microphone mounted on the printed wiring board, a housing having a sound hole for receiving the sound while accommodating the printed wiring board, and a microphone mounted on the printed wiring board in a non-contact state And a microphone unit in which the printed wiring board and the sound hole surrounding portion of the housing are connected by a pipe-like structure, and the main body is made of a hard material of the pipe-like structure. A microphone unit characterized in that a flexible material is joined to one end face of the microphone unit , and the connection is made substantially by compressing the flexible material . And the printed wiring board, and a microphone mounted on the printed wiring board, and a housing having a sound hole for introducing sound into the upper together with the printed circuit board is housed, a microphone that is mounted on the printed circuit board non A microphone unit having a structure in which the printed wiring board and the sound hole peripheral portion of the housing are connected by a first pipe-like structure included inside in a contact state has a sound hole to which the microphone unit is to be attached. Each sound hole is placed on one side of the plate-like structure having the sound hole, and the decorative plate having the sound hole is similarly placed on the other side of the plate-like structure to which the microphone unit is to be attached. microphone connected to the sound hole and the veneer sound hole of the microphone unit in the second pipe-like structure with the arranged Te The second pipe-shaped structure is integrally formed on the decorative plate, and the mounting boss provided on the decorative plate and the lower portion of the casing are tightened with screws to form a second knit. A microphone unit mounting structure , wherein the pipe-like structure is closely connected to the periphery of the sound hole of the microphone unit.

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